The DEKPA is the Pleasure Craft Traffic Document used for recreational boats in Greece. AADE's TEPAI brochure ties it to the fee: to issue or attest a DEKPA you must pay at least that month's TEPAI, and from then on TEPAI is paid month by month.
What a buyer checks
Whether the boat has a DEKPA or, for a foreign yacht, a transit log, and the TEPAI receipts that go with it. Changes of owner or details must be entered in eTEPAI at the next payment, with the documents kept on board. See buying a boat in Greece.