Spearfishing locations and guides Greece

Greetings,

Me and my friends are coming to Greece from Serbia probably in August to hike mountains a few days and later go to the sea. I'm interested to try spearfishing. Tried it in Montenegro last year but since i was clueless what terrain to look for and how to hunt, it wasnt very enjoyable or rewarding.

Do You have any suggestions where in Greece is good for spearing, since we are a on a budget and have limited options that are not too far from our planned route.

Possible regions that we can go are Stavros side in Chaklidiki and Lefkada near places on west side. But Corfu is excluded because of budget (even though i heard that its good destination for spearing).

Also are there any guides or people that are willing to take you to some locations or help us a little?

P.S. about equipment and skills, i am seasoned freedivier, not too advanced Also I'll bring all the equipment.