Founded in 2006, by Vassilis Antonas, Impact is the longest standing Greek firm, specialising in Executive Coaching and Organisational Development. Our company has provided services to over 60 Greek and multinational companies and is the pioneer of the first and longest standing Coaching Training in Greece; the Diploma, which was launched in April 2008 and has run consecutively, every year, since. In 2014, our training was globally the first to receive Accreditation from the Association for Coaching; at top tier (AADCT 4/4).

Our vision is the Evolution of Leadership.

Our mission is to align performance with vision and strategy for individual and corporate leaders.


What: Executive Coaching is the theory and practice of an agent of transformation, supporting a professional’s awareness, leadership and talent, through behavioural and business interventions, within an organisational context. (Antonas, 2017, Coaching for Impact, Routledge, pg 4)

Why: Amongst other benefits, executives and leaders can expect to enhance and improve their pace, resilience, accountability, influence and deliberation.

For Whom: C-level executives, high potentials, management, entrepreneurs, leaders in business.

How:  Coaching comes in clusters of six 45 minute meetings, which can be repeated as many times as necessary. 

  1. A no-obligations chemistry meeting between the executive and our coach. 
  2. kick off meeting between all stakeholders (such as the Head of HR, the line manager if applicable etc) to set expectations and deliverables at the beginning of the engagement. 
  3. Six 45-minute coaching sessions (The cycle of 6 can be repeated). 
  4. A follow up meeting between stakeholders to assess progress at the end of the engagement.

A completely customised 360 will be designed and employed if deemed useful. 

What: The process of aligning collective performance and behaviour with the organisation’s vision and strategy.

Why: To optimise team functioning; to generate common context and direction; to align performance with values, culture and strategy; to foster transformation.

For Whom: Board of Directors, Management Teams, Functional, Sales Teams and Project Management teams. 

How:  A fully customised intervention based on 4 principles: 

  1. Needs assessment based on rigorous data collection.
  2. Cutting edge intervention design based on needs assessment.
  3. Intervention delivery comprising individual coaching, individual and team assessment, workshops, peer coaching, customised 360 surveys and more.
  4. Calibration follow up.

Our workshops are divided equally between skills training, practice and reflection and are based on constant interaction, live feedback and a move-forward attitude. All workshops can be delivered over one or two days for teams of 8-16 leaders and can be customised. Our facilitators all carry OAED LAEK certification and your company can benefit from the the relevant subsidy.

The PRAID Leadership Model

A transformational yet fully applicable leadership model, directly from the field: PRAID combines every possible skill, quality and asset that leaders will need and utilise on their way to the top. Uncompromised and unapologetic, this workshop amalgamates Vassilis Antonas’ work with Senior Leaders over the past two decades and forms the cornerstone of his book, Coaching for Impact (Routledge, 2017). 

Coaching Fundamentals

Coaching can prove immensely useful when done right. It can also be plain counterproductive when done wrong. This workshop is an absolute performance accelerator, since it provides leaders with the fundamental skills that will enable them to coach their teams and their peers with focus and deliberation, whilst avoiding the usual pitfalls.

Conflict Management

Learn the basic platforms of conflict, assess your conflict management style and learn to identify polarities that will metabolise clash into opportunity. An invaluable learning experience that will sustainably enhance collaboration, communication and consequently performance within teams. 

Building Organisational Trust

Mistrust, doubt and suspicion can prove very costly for corporations. In the end, it all tends to form a communication gap that renders collaboration and progress implausible. Our workshop not only practically prescribes how to overcome all that, but also serves as a bridge towards building team spirit and rapport, whilst speeding up delivery. Very few other interventions can match it.

Success Factors in Project Management

Project based work is here to stay. Its effective and strategic management can and will determine profitability, sustainability and business success. Supporting the maturity of individual skill sets and organisational parameters in project management is, at this stage, a one way street. Based on international best practices and global standards like PMI’s and ISO 21500, this training will reform and transform your project managers and their team in an unprecedented way.  

NLP for Business and Personal Transformation.

Timelines, values, anchoring, linguistics, rapport. Enter the world of Neuro Linguistic Programming (NLP), a synthesis of Cognitive and Behavioural Psychology approaches, considered the “manual” of the mind. This manual can be utilised to consistently achieve specific business and personal outcomes. This transformational workshop based on the ABNLP (American Board of NLP) best practices and certifications, focuses on the NLP tools that enable an accelerated transformation of the participants. 


Diploma in Executive Coaching and Organisational Development (AADCT)

Founded in April 2008, our Diploma is the first and longest standing coaching training in Greece. In 2021, our training enters its 14th, consecutive intake. Featuring a carefully selected faculty of expert facilitators, counting over 160 influential alumni and spanning 120 hours of top-quality training, in 2014, it was globally the first course to receive Accreditation from the Association for Coaching; at top-tier level 4/4. In 2021, our Accreditation was renewed by the Association for a further 3 years. 

We have been entrusted with transforming leaders from companies and organisations such as Abbvie, Accenture, ALBA, AstraZeneca, BAT, BDO, Center for Democracy, Cognity, DHL, DMG Mori, Evolution Dojo, Eletson, Elval, Fweebi, Great Place to Work, Information Society, Innora, Jewish Community of Athens, Knowledge Training and Consulting, Microsoft, Mondelez, Nike, OTE Academy, PM Partners, Pharmathen, Rigips, Starbucks, Star Channel, Simply Burgers, S & B, Stoiximan, SC Johnson, Unilever, Vestas, Wyeth, 1Source – Aero Services – as well as several consultants, entrepreneurs, journalists, publishers, mental health professionals, project managers, football coaches, martial art instructors and other leaders of transformation.

Course Accreditation:

  • In November 2014 our training program became the first to be awarded Accreditation by the Association for Coaching, globally.
  • The Diploma is accredited at level 4/4, Accredited Advanced Diploma in Coach Training (AADCT), which is the top tier. In 2021, our Accreditation was reviewed and renewed by the Association for a further 3 years.
  • The Diploma is awarded by Impact, an Organisational Member of the Association for Coaching.
  • Individual Accreditation can also be obtained upon completing the requested hours of coaching practice and subject to meeting all other application criteria. (Please visit the AC website for more details).
  • Impact can provide supervision towards completing full membership and accreditation requirements.

The course provides 120 hours of Continuous Professional Development Units (CPDU) as indicated on the certificate.


OTE Academy

Lunch, coffee and refreshments inclusive

Full provisions have been made, in order to run every module either on a web platform or live, subject to the Covid-19 circumstances.

Association for Coaching

Course Dates for 2021-22

AprilSaturday 10 + Sunday 11

Vassilis Antonas:
Fundamentals of Executive Coaching & OD
MayFriday 14, Saturday 15 + Sunday 16
Vassilis Antonas:
Transformational Leadership: A Jungian Perspective
The Evolution of Leadership: Leading with PRAID
Coaching for Impact: A Complete Method
JuneFriday 11 + Saturday 12
George Diakonikolaou:
NLP Coaching for Impact
JulyFriday 9 + Saturday 10
Tereza Venetsanou:
Systems & Organisational Development
July to SeptemberStudy Period
SeptemberSaturday 25 + Sunday 26
Stella Ioannidou & Yiannis Kanoutos:
Human-Centred Coaching: A Framework
Apodosis Team:
Enhancing and Developing Influence
OctoberSaturday 30 + Sunday 31

Renos Papadopoulos:
Leadership Transformation: Surviving and Thriving through Adversity

November to January
Placement Delivery, Presentation Design & Thesis Preparation
JanuarySaturday 15 + Sunday 16

Vassilis Antonas:
Placement Presentations
Association for Coaching

Entry Requirements

  • Graduate academic qualification
  • 1 year’s experience in OD, Consulting, HR, Counselling or Management
  • Minimum age requirement 25
  • Good command of the English language
  • Personal maturity and capacity to challenge your reflective learning curve

Admission Process

  • Submission of CV
  • Submission of paragraph stating experience and aspirations in coaching and OD
  • Interview with Course Director
  • 50% down payment

We accept an average of 65% of applications received


  1. 3,500 word case study or research: assessed by the Course Director and/or Facilitators and externally validated if necessary or in case of dispute
  2. Attendance (85% minimum required) and contribution
  3. Successful completion of practice/placement and case study presentation (Impact will assist you in finding a voluntary unpaid placement within one of our client companies, but does not guarantee one. The placement can be a team OD intervention or individual coaching. In both cases 3 meetings will be required-one for data collection, one for intervention and one follow up. We have so far secured a placement for all alumni): Peer Assessed.**
  4. Written examination on theory, covering the core material taught and reading list***
*Each one of the 4 assessment areas carries equal weight (25%) and must be successfully passed (60%) to secure a certificate
** In addition a 60 hour coaching practice log must be submitted in order to receive the Diploma as required by the Association for Coaching.
***The Graduation/completion rate is approximately 85%, subject to successfully completing and passing all assessment criteria.

Contact or call +30 2108014505 to receive the complete syllabus

Association for Coaching

Vassilis Antonas, Director

Executive Coach, Psychotherapist, Organisational Development Consultant and Course Director of Impact’s Diploma in Executive Coaching and Organisational Development (AADCT), globally the first Coaching Training to receive Accreditation from the Association for Coaching. Vassilis is the author of Coaching for Impact: The Evolution of Leadership, published by Routledge in 2017.

He has consulted for over 60 Greek and Multinational companies, delivering tens of thousands of consultation hours to leaders from all functions and industries. Clients include Microsoft, Alcon, Nike, NN, Unilever, Mondelez and more.

From 1998 to 2001, he worked for the British NHS and served as Clinical Director for CAP London from 2001 to 2006, at which point he returned to Greece and founded Impact. His vision is to craft the circumstances for pursuing excellence for individuals and organisations: Directly, by offering Executive Coaching and Organisational Development services and indirectly through the Diploma.

Vassilis is also a composer, a martial arts instructor, a free diver, former motorsport driver and devoted world traveller.

Professor Renos K. Papadopoulos, Ph.D., Diploma Facilitator

Renos Papadopoulos is Professor of Analytical Psychology and Director of the ‘Centre for Trauma, Asylum and Refugees’, also, a member of the ‘Human Rights Centre’, of the ‘Transitional Justice Network’ and of the ‘Armed Conflict and Crisis Hub’ all at the University of Essex, as well as Honorary Clinical Psychologist and Systemic Family Psychotherapist at the Tavistock Clinic. He is a practising Clinical Psychologist, Family Therapist, Jungian Psychoanalyst and Organisational Consultant. As consultant to the United Nations and other organisations, he has been working with refugees, tortured persons and other survivors of political violence and disasters in many countries. He offers specialist training and organisational consultancy internationally, and his writings have appeared in fifteen languages. Recently, he has been given Awards by the European Family Therapy Association for Life-time ‘Outstanding contribution to the field of Family Therapy and Systemic Practice’, by the University of Essex for the best ‘International Research Impact’, and by two Mexican Foundations for his ‘exceptional work with vulnerable children and families in Mexico’. 

Dr. George Diakonikolaou, Associate

George Diakonikolaou is the Managing Director of “Project Management Coach” LTD, delivering services to business clients in the fields of Project Management, Leadership, Coaching and Organisational Development. His clients include companies such as Cosmote, Romtelecom, Vestas, ENEL, EDF etc. George is a visiting Faculty, teaching Project Management in the International MBA in Athens and Brunel Business School, MBA in London as well as Bradford Business School. He has received his First Degree in Electrical Engineering and Computer Science in National Technical University of Athens and his M.Sc. and Ph.D. in Computer Science from University of Manchester Institute of Science and Technology. George is the co-founder of the Greek Chapter of the Project Management Institute, a Certified Project Management Professional and a founding member of the Hellenic Coaching Association. He is also an NLP Trainer and Master Practitioner of NLP & Time Line Therapy®, a Master Practitioner of Hypnosis and an NLP Master Coach.

Currently, George is experimenting with the integration of Coaching, Organisational Development and Project Management in a field that he likes to refer as “Project Coaching”, an integrated model that achieves groundbreaking results in Strategic Projects, Programs & Portfolios, and executive teams’ performance.

George is a 2010 Diploma Alumnus.

Tereza Venetsanou, Associate

Organisational Development and Business Transformation Consultant, Executive Coach and NLP Master Practitioner. Originally from a marketing background, Tereza has held leadership positions in multinational corporations such as Microsoft, Vodafone Global Enterprises and Wind. Currently, she is leveraging her corporate experience paired with coaching skills to consult and advise senior business leaders in the creation of state-of-the-art business models and solutions. Whilst supporting Impact through a combination of business development, training and coaching expertise, she is also supporting Vodafone Partner Services as a Sales Transformation Consultant.

Her focus has always been to drive and accelerate sales and business performance through people. She is as competent in generating marketing plans and supporting strategic priorities as she is in coaching senior leaders and building strong teams. During her career, she won numerous awards for extraordinary achievements and has a track record for successfully implementing transformational initiatives both at Vodafone Global Enterprises and at Microsoft. Her vision is to empower teams and individuals to reach their full potential within their business context.

She is a mother of two, devoted in personal development, constant learning and travelling.

Tereza is a 2019 Diploma Alumna.

Katerina Nikoloutsou, Diploma Facilitator (Apodosis Team)

Executive coach, Music Coach, Europeanist and Master of Education (M.Ed), during the last 25 years, Katerina, has trained thousands of children, adults, people with special needs and professionals. In 2009 she founded Mousiko Parathyro, a Music Coaching Centre in Athens with the mission to explore one’s musical personal self. As an executive coach, she specialises in the use of voice for leaders of any background and the enhancement of their persona.

Katerina is partner in Apodosis Coaching Services and her vision is to give prominence to the fundamental role of voice and one’s self as a tool for development and evolution.

Katerina is a 2017 Diploma Alumna.

Eleni Marina Ioakeim, Diploma Facilitator (Apodosis Team)

Executive Coach, HR Executive, MSc in Strategic HR Management, Eleni’s background in Economics gave her the opportunity to work in various organisations and get a deeper understanding of people’s impact. Eleni specialises in translating business vision into HR initiatives that improve performance, profitability, growth, and employee engagement.

Her training as an executive coach contributed to her vision of supporting professionals with maximising their apodosis, always in alignment with her experience in communication and team building. She is partner in Apodosis Coaching Services since 2020.

Eleni is a 2019 Diploma Alumna.

Lampros Zolotas, Diploma Facilitator (Apodosis Team)

Executive Coach, Triathlete, Tech Leader, MSc in Organisational Development & Change Management, Lampros is the Country manager of HMD Global and Partner in Apodosis Coaching Services. He has worked for 15 years in business development and leadership roles in Motorola, Nokia and Microsoft. His key coaching practice focuses on developing executives to reach their fullest potential, through influence and accountability.

Whilst training for his first Half Ironman triathlon, he has been mentoring students for the University of Manchester, as well as SMEs for Endeavor and startups for Foud.ation and KEMEL. 

Every day is an opportunity to become better and we all have the right for a bad day.

Labros is a 2017 Diploma Alumnus.

Stella Ioannidou, Diploma Facilitator

Stella is a Reskilling Expert who finds joy by driving skilling efforts and strategically managing Change while promoting Engagement, mainly through Talent Management & Learning and Development initiatives. She is also a Senior Faculty Member at the Josh Bersin Academy, facilitating the upskilling efforts of Academy members for the largest HR professional development network in the world. When she is not volunteering as an aspired Executive Coach for Individuals and Start-ups, she blogs about the competencies of Motherhood and how business-relevant they are.

Stella is a polymath, continuously exploring the extents of her knowledge base to sharpen her ability to transfer tools and ideas to enrich her practice: she holds an M.Eng. in Rural & Surveying Engineering and a M.Sc. in Information Systems Management from the National Technical University of Athens, an MBA from ALBA, and currently pursuing her M.A. in Adult Education and Vocational Training. She is a certified Project Manager (PMP®), Agile HR Professional (ICP-AHR), Change Management Practitioner (APMG), and IASSC Certified Green Belt. She practices vulnerability through singing while playing the guitar. She has co-developed Human-Centered Coaching to help foster a world where everyone brings their whole-self to the table.

Stella is a 2015 Diploma Alumna.

Yannis Kanoutos, Diploma Facilitator

Yannis is an all-around facilitator driven by continuous improvement, empathy and story-telling, who loves bringing the human aspect to the way companies operate and to the products & services they offer. He often expresses the belief that technology may be the driver to the design of different products and services, however success still lies on how strongly the human factor is involved and if real needs are met. 

He is a certified Change Management professional (APMG) with extensive experience in the Finance industry, especially in the field of Business Analysis (he holds a MSc in Information Systems and he is also IASSC Certified Green Belt). He often contributes as a Coach for Teams that practice human-centred methodologies, since he is a certified Design Thinking facilitator (Dynargie). He is a firm believer in multidisciplinary collaboration and goes about asking teams “why”, as a means to deepen the understanding of needs before addressing challenges.

Yannis’ approach combines a blend of methodologies that maximise a Change’s impact: he draws from a variety of different tools and methodologies and operates as an internal consultant working diligently to shift mindsets and help create impactful product and service offerings.

Diploma Testimonials 2020-2021

The Diploma was a life changing experience. Being able to transform myself, realizing my limiting beliefs and the obstacles I create sabotaging myself, were a huge revelation for me. Understanding where people come from, understanding their processes, provided me with an advantage (work & personally) and a much calmer life. The bonus was meeting wonderful tutors who escort you all through this journey and talented peers supporting and learning from each other but more importantly complimenting each other. I am certain the tools & skills provided in the Diploma, will be of great use in my current as well as future professional endeavors, but also in my personal life. Best gift I gave myself!
Taly Mair (Jewish Community of Athens)

Designed to re-engineer mindsets and change life-cycle patterns through carefully structured experiential activities, Impact’s Diploma offers a one-of-a-kind opportunity for those determined with resilience and deliberation to follow a pace where accountability leads to influence.
Dimitris Koroniotakis (Pharmathen)

Do not take this course unless you are ready to dig deep inside you, challenge everything you have done until now, change the way you communicate with others, evaluate your personal and professional relationships, question your values and your moral compass. In short, do not take this course unless you are ready for an inside-out transformational journey that will change your life and make you a better person.
Aggeliki Korre

A unique opportunity to raise your self-awareness and to understand others. The whole experience cannot be captured in words. It is the best investment somebody can make, with a remarkable ROI. I have never experienced so far, anything more intense, challenging and deep. No matter how many hours it lasts, you always want more! I highly recommend it.
Danae Stylianou

A great journey to self-awareness and self- development. The structure and the methodology of the course, the excellent team of instructors/consultants and the quality of co-participants, make a great combination that leads to a once in a lifetime experience. It works equally good, Face2 Face but also on-line. It is demanding, but also rewarding. Highly recommended!
Manos Vlasis (OTEAcademy)

A friend of mine, who I deeply respect, took the diploma one year before me. He was overwhelmed by the interaction, the authenticity and the transformation of the group he was in. I decided to take it myself, as a personal challenge, gain of knowledge and self-awareness. I would never anticipate how much fun, warm and friendly this group of people would be. It’s worth the time, the money, the effort and everything you have to give to this life experience.
Nikolaos Milidakis (Lidl)

An excellent organized and structured program. Integrated modules, inspiring instructors, high standards training material and case studies, all aiming towards creating and developing “agents of transformation”. Diploma is a challenge! A challenge someone can take towards, relations, risks, self-awareness aiming to find the “Authentic Self”.
A never-ending journey full of experiences and knowledge. Do not miss it!
Stavroula Bertzouani

I strongly recommend the Diploma in Executive Coaching and Organisational development.
It is a unique tool that helps you work with yourself and human ecosystems. It helps you develop all the necessary techniques in order to increase your impact and your influence. A unique experience, a journey I will never forget.
Thank you Impact.
Nikolaos Maragopoulos

Diploma has been a great journey into further comprehending my “process and content” and how I am perceived by others. I strongly recommend it to any business leader wanting to grow professionally and personally and engage in more meaningful and impactful interactions.
Antonis Oikonomou (Microsoft)

To view a full list of our testimonials click here


Our consultants have provided Executive Coaching, OD consulting, Corporate Counselling and Training to several clients in Greece and internationally from different industries and functions.
List of all clients….

Your Team

Vassilis Antonas
Vassilis AntonasFounder, Managing Director, Diploma Director
George Diakonikolaou
George DiakonikolaouAssociate
Tereza Venetsanou
Tereza VenetsanouAssociate

Contact Us

1E Adamon Street, 145 64,
Kifissia, Athens, Greece
Tel: +30 210 8014505