Native salmon still enter Tomales Bay and spawn in Papermill Creek. During winter storms, the creeks add significant amounts of freshwater to the bay. Tides fluctuate in the range of 6 feet for the most part, depending on season and phase of the moon. The outlet to the ocean is at the north end of the bay, which happens to be the southern end of Bodega Bay. On a clear day you can see Bodega Head from certain locations on Tomales Bay.
The San Andreas Fault runs directly beneath the bay, creating a dramatic difference between the western and eastern shores. Primarily a result of the different geologic features, the two regions and their associated micro-climates and ecosystems make for some of the best paddling I have ever done.
Tomales Bay has it all. If you are a beginner or just want to take it easy, you can cruise the shoreline looking for critters in the intertidal zone, paddle short distances between little resting coves, and most of the time, stay out of the wind by paddling close to shore. Spring is the windy season. I camped in August and there wasn't very much wind at all.
For more challenging paddling you can go out on the Bay at night or take your kayak out the mouth of the bay towards Tomales Point. There is surfing at Dillon Beach and you can get out to some big water paddling along the Pacific Coast's exposed shoreline. I did not go out this trip, but would like to in the future.
Camping on the western beaches is pretty incredible, especially up north near the mouth of the bay. Wildlife is abundant and spectacular. Harbor seals, Tule Elk, Leopard Sharks, Thresher Sharks, Bat Rays, tons of Birds, River Otters, Deer, Bobcat (I saw tracks), and Sea Lions.
The beaches are pretty and you can find one all for yourself if it isn't too busy. Some of the beaches have hiking trails up to the ridge where you can get views of the Bay, the Ocean, and Bodega head to the north. The water is crystal clear. On calm days I was looking down into the water 15-20 feet to the bottom. Kelp, eelgrass, starfish were all clearly visible.
At night you can have a campfire, if the fire danger isn't high. There really aren't any facilities along the coast, so you must bring in all your water and pack out your waste. I camped for 3 nights and would like to do a longer trip. There is a lot to explore here.
Contact the national seashore or an outfitter regarding conditions and restrictions. I got some good advice at Point Reyes Outdoors, a local outfitter in Point Reyes Station. Permits are available the park's visitor center and are required. Summer is the busy season but you can paddle/camp year round.