Hi....Island Hoppa gave you a lot of good information. Ypao beach is real convenient (near the Hilton Hotel in Tumon) and has lots of little blue chromis, cornet fish, sometimes schools of mullet, etc. The deepest you'll find is only about 8'/2.5m, though. Generally it's not practical to snorkel there past the reef, as it's a long walk (or swim at high tide) over the coral....which you shouldn't be walking on anyway, of course. Another easy, safe snorkelling place if Fisheye park, directly across from MDA...about a 15-minute drive from Tumon. Another place I'd recommend is Gun Beach, down an absolutely horrible road behind the Nikko Hotel. There's a cut in the reef made for telephone cables, which makes access to the deeper water quite easy. Just be careful of 1) big waves and 2) thieves. Your vehicle should not have any valuables in it, or at least they should be kept in the trunk. A locked door seems to mean "please break me with a rock & see what I'm hiding in the car."
As for the diving itself, there are lots of nice dive sites...but the "big" stuff that you'd be likely to see in Palau (mantas, sharks, schools of barracuda, etc) are not very common here. I've seen all of the above here....but on most of the dives, don't really expect to see them. Outside the harbor (where the boats go unless the waves are very big) the visibility is usually over 120'/40m or so. Inside the harbor it is more around 1/3 to 1/2 of that. Still not bad. I have a website which has a bunch of site descriptions & some photos from the different dive sites, if you feel like taking a look
www.letsdiveguam.com
I tend to see a turtle or two most often at the Crevice, up around 40'/12m, heading back towards the cliff line. As far as wrecks, you mostly need to do them from a boat... And there's a catch-22 with diving them....usually, if the weather is good, the first (deep) dives are typically done OUTSIDE the harbor (Blue Hole, Crevice, Barracuda Rock, Hap's Reef being the most popular) and the 2nd dive is usually fairly shallow, so the wrecks aren't often done. In BAD weather, when the boats can't get outside, they hit the wrecks (figuratively speaking, ha ha) quite a bit. The Tokai Maru/Cormoran combo & American Tanker are most often done, but there's also the Val Dive bomber (not too much of it left) and the Kitsugawa Maru (deep). I've done the Tokai a few times from the beach, but it's about a 25-minute surface swim, which isn't for everybody. The American tanker would be a steep climb down a rock embankment, and then it's just off shore, but you're probably unable to drive down the breakwater to get near it....in fact, I'm not sure "individual" divers are allowed access to the beaches in the port (where the wrecks are)....dive shops & employees are required to have insurance listing the Port Authority as insured, and go through a police checkpoint to get there. Anyhow, a long way of saying that you'll probably need to get on a boat for wreck dives. Sometimes the big shops have a dive schedule listed which might include the wrecks; you should check that out...otherwise, it's mostly "group consensus" to determine the dive sites on the way there. One other inside the harbor site I'd recommend is Gab Gab 2....the Atlantis submarine goes there & feeds the fish, so you get a school of big jacks aka Giant Trevallies...about 20 of them, plus batfish swirling around you. Pretty neat.
Hope you enjoy your diving here!
