My girlfriend and I are planning a 2 week trip to Greece at the beginning of July. We are looking for a relaxing beach vacation and would like to visit between 2 and 3 islands on this trip. Main criteria are nice beaches, beautiful surroundings, good food and ideally good snorkelling/diving locations.
We have done a little research and the choices appear to be either the Cyclades specifically Naxos, Santorini and Spetses
OR
the Ionian side specifically Lefkada and Paxos.
Can you please advise which side you think fits the criteria and if you have any amazing suggestions on accomodation or other island destinations it would be much appreciated


LOL you have chosen the most overcrowded and not relaxing islands instead ideal for your relaxing beach vacation are the Dodecanese islands especially thr small ones like Lipsi Nisyros Symi or Leros

I don't agree with the suggestion that Naxos, Santorini and Spetses will be overcrowded in the beginning of July.
Most islands don't get overcrowded until after mid July so I wouldn't rule out that option. Keep in mind that Santorini's beaches are mostly covered with pebbles and are not your classic Greek sandy beaches. Santorini does offer ideal diving locations! Naxos has one of the best and longest sandy beaches in Cyclades. Both places offer excellent food but be sure to look around before sitting down on the first restaurant you come across.
Take a look at any of these guides for
Naxos or Santorini
HTH.