During his visit, the Commissioner, who is responsible for regional policy and structural funds, will meet Welsh Ministers and visit a range of EU projects.
It will be the Commissioner's first visit to Wales and comes as almost £1.6bn EU funds have been invested by the Welsh Government across the region since the current funding round began in 2007.
The visit follows the First Minister’s trip to Brussels in February this year to further strengthen Wales’s links with Europe.
The First Minister said:
"It is a pleasure to welcome Commissioner Hahn to Wales and have the opportunity to discuss the opportunities to maintain and grow Wales’ links with Europe.
"The fact he is here is a clear sign of the benefits of engaging with Europe and I want to maintain our close working relationship.
"There are real benefits to our membership of the EU. It is one of our major trade partners, a destination for Welsh goods and services. European funding helps support businesses and communities across the country. I want to see these benefits to continue to proposer and support the economy of Wales."
While in Wales, Deputy Minister for European Programmes, Alun Davies, will show the Commissioner how EU funds are being invested at Swansea University during a tour of the EU-backed Institute of Life Sciences 2 - a hi-tech medical research facility which houses the pioneering Centre for Nanohealth project. They will also meet young people at a computer programming workshop made possible through the EU-funded Technocamps project, which helps young people to take up subjects in Science, Technology, Engineering and Maths to improve their career prospects.
There will also be a visit to the SA1 Waterfront development where the regeneration of Swansea's docklands is transforming the city into a vibrant place to work and live thanks to EU funds.
Deputy Minister for European Programmes, Alun Davies, said:
"We are committed to ensuring our European programmes are amongst the most successful in the EU for shaping the conditions for sustainable growth and jobs for the future. EU projects, delivered in partnership, have already helped 86,500 people to gain qualifications and 36,500 into work, while 11,000 (gross) jobs and 2,150 enterprises have also been created. I look forward to showing Commissioner Hahn some of the innovative ways in which we are investing EU funds here in Wales."