Tomales Bay is a protected area, so those obnoxious personal water craft and jetskis are not permitted.
Kayaking and sailboating, however, are both allowed. If you happen to have your own boat, there are a couple of places where you can launch the boat - Heart's Desire Beach (you have to carry your boat for about 100 yards), or Golden Hinde Inn (there is a launch fee).
If you don't have your own boat, you can rent kayaks at Blue Waters Kayaking in Inverness.
Pictured here is the Golden Hinde Inn Marina.
If you've got a real burning desire to swim in the sea in Marin County, Tomales Bay is the place to do that. The water is safe, unlike the Pacific side beaches (see my Warnings and Danger tip). However, I really don't know why anyone would want to swim in this water - it is FREEZING, even in summer.
If you must, go to Heart's Desire Beach at Tomales State Park. There is an entrance fee. At this beach, you can wade in without fear of being swept away and watch your extremities turn blue.
This cocky sea gull decided he needed to be included in my picture just as I was looking for the perfect photo op on Tomales Bay.
Point Reyes is a popular spot for bird watching and you should see more interesting birds than this ordinary sea gull.
Favorite thing: Tomales Bay is the long bay that separates Tomales Point from the mainland. The San Andreas Fault runs directly underneath the length of the bay - the Bay was actually created by earthquakes along the fault.
Favorite thing: Some of the mountain bike trails in the area are easements over ranch lands. You'll need to share the road with the cattle along the way.