We will be staying in a small village, la Croix-Valmer, south of St. Tropez, in late May, early June. We'd love to visit the Iles d' Hyeres, possibly doing some hiking,and maybe snorkeling or sea kayaking, if feasable).

1) Which island(s) would folks recommend we explore?
2) What would you recommend seeing or doing?
3) Is there a way/place to snorkel or sea kayak?
4) What would be the best way to get to the islands, We'll have a car, but also enjoy using public transportation.

Thanks for any help with this - I know there are some Provence experts out there and I'll probably have more questions as we plan our trip to the area.

Wren2: we will be staying in Le Lavandou early June and plan on doing the same excursion!
Very long time ago (late 70's) we visited Ile de Porquerolles and Ile de Port-Cros. Porquerolles is the larger one that is more touristy and has some hotels, restaurants and shops. At the time they were very quiet little islands, perfect for walking or cycling. Ile du Levant is known as a paradise for naturists.
As far as I know there are no cars allowed on the islands.
There's a ferry service from the port of Hyères to Port-Cros ; from La Tour Fondue (Giens) to Porquerolles and Port-Cros.
Time tables at http://www.tlv-tvm.com
'Les Vedettes' ferries go from La Croix-Valmer, Cavalaire and Le Lavandou to Porquerolles. From Le Lavandou to Port-Cros and Le Levant.
Time tables at http://www.vedettesilesdor.fr

I visited Portquerolles once and it seemed idyllic, but I don't know the other two islands. The two main boat operators are www.vedettesilesdor.fr and www.tlv-tvm.com; the latter run from La Croix Valmer in July and August, but it looks as though the nearest port in May and June would be Cavalaire. You can't take a car to these islands.

Thanks for the web-sites. We'll definitely check those out. I wondered if they were car or passenger ferries - I'd rather leave the car on the mainland in any case.

Any suggestions for specific restaurants for lunch, or would a picnic be a better option?

The rates stated on the websites are for passengers only.

You certainly can't take a car to these islands - the islands are small and have few roads.