Hi John,
and welcome to the site of Hellenic Association of Recreational Divers “Tethys”

It's a big compliment for us, you are patient enough of using Google translator to read the forums in here
From a scuba point of view, a lot of things have been improved in Greece since 1996 and we hope that they will continue to imrpove.
Regarding scubadive allowance in Greece, according to the new law of 2005 [
Ν3409/2005 - (ΦΕΚ 273)] you can now dive almost everywhere.
The main points of the new law are:
(a). You have to be a certified scuba-diver with a diploma of a scuba-organization recognized in Greece
(b). You are not allowed to dive alone (i.e. you need a buddy)
(c). You are not allowed to dive in certain places which:
- are characterised as archeological sites OR
- are characterised as potected "Natura 2000" areas OR
- are dangerous for diving (such as the entry of a harbor or commercial ships-routes)
(d). If you want to dive at night (=1 hour after sunset up-to 1 hour before sunrise) you must ask for a specific license from local port authority (Τοπικός Λιμενικός Σταθμός) or dive using a local Dive Operator
If you need any special information, don't hesitate to contact us.
We will also be glad to dive with you, next time you visit Greece.
Cheers

Fivos