Last updated: March 19, 2023
Only when waters recede at a low tide does the intertidal zone reveal its majesty to the careful explorer. This is a realm inhabited by magnificent creatures that look as if they came from another time and world. Many creatures living here resemble those who lived thousands of years ago. The intertidal zone exists halfway between land and sea on the rocky shelf where waves break and splash against rocky outcroppings.
When to Go
Plan ahead for successful tidepooling. Tides for Point Reyes are available from NOAA Tides and Currents. The best time to go tidepooling is during a minus low tide. Note that not all low tides are minus tides and some low tides are not low enough for successful tidepooling. Be at the tidepool area at least an hour before low tide so that you have plenty of time to explore safely while the water is receding. Return no later than an hour after the tide has begun to rise.
Where to Go
The best tidepools at Point Reyes are found at Sculptured Beach, near Coast Camp. Duxbury Reef near Agate Beach in Bolinas, outside of park boundaries, is another good place to tidepool.
From Bear Valley Visitor Center, 20 minutes driving plus 1 hour walking.
Drive to the end of Limantour Road and park near the beach. Walk down the trail to the beach and turn left (south) on the beach. Sculptured Beach is approximately two miles south of Limantour Beach. Do not go past the rocks if the tide is coming in. At high tide, there is no way out!
From Bear Valley Visitor Center, 25 minutes driving plus 5 minutes walking.
Drive to Bolinas on Highway 1. Turn right on Mesa Road, turn left on Overlook, then right on Elm. Follow Elm to the end and look for signs to Agate Beach. This is the most extensive tidepool area near Point Reyes National Seashore, and has the most gentle return of the high tide. This is a good spot if you are tidepooling with children. Agate Beach Park is managed by the Marin County Department of Parks and Open Space.
Exploring the Intertidal Zone
In the intertidal zone the ocean rises and retreats twice each day. Its inhabitants are exposed alternatingly to immersion in salt water and exposure to air. The animals that survive in this sometimes wet and sometimes dry habitat are mostly invertebrates. These animals use their ability to adapt to their changing environment to escape predators. Many of the plants in the intertidal zone are algaes. Observe how the different algae and kelp species change to help distinguish between tidal zones.
High Intertidal Zone
The high intertidal zone is the area closest to the beach. It is covered with water only once or twice a day during high tides. Here, look for small, round, one-piece shelled mollusks called ribbed limpets. They live among acorn barnacles which are white, volcano shaped shelled arthropods found glued to rocks. Eroded periwinkle, small-shelled snails, and black turban snails are species of gastropods (snails) found in the high intertidal zone. Periwinkle is a species found worldwide in the intertidal zone. Look for a spiral pattern in its shell similar to that which you find on its land dwelling relative, the garden snail, often seen roaming in your home garden. The black turban snail is another spiral shelled snail. Look for its black color spiraling up to an iridescent center. Take an extra look to see if the shell is indeed inhabited by a snail, or if a hermit crab has moved in. Rock weed (a type of brown algae) is easily identified by pairs of air pockets located on either side of the main vein running through the kelp. Try and spot lined shore crabs in rock crevices or by turning over rocks.
Middle Intertidal Zone
In the middle intertidal zone the creatures, rocks, and kelps are exposed at least once a day by tidal fluctuations. The animals of this zone cover themselves with sand and bits of shells to prevent water loss from exposure to wind and sun. Look for the ochre star. It is a purple or orange sea star which uses its tube-feet to cling tightly to the rocks. The sea star pushes water through an internal canal system to move water through its tube feet in order to hold on to the rocks, move around, and to feed. The mossy chiton, a small, flattened, oval mollusk with eight exposed plates on its back, is a treat for the diligent observer. Sea lettuce, a green algae, can be identified by its bright green color and wavy edges. It can be found attached to rocks both here in the middle intertidal zone and estuaries. Goose barnacles are also found in the intertidal zone.
Low Intertidal Zone
The low intertidal zone is the area exposed only during a very low tide. Look for purple sea urchins thriving amid strong wave action. These remarkable animals move along by gripping rocks with tube feet and shoving its body forward with its teeth collecting small plants along its way. One may also find the bat star, a sea star which is webbed between its arms. Giant green anemones, growing up to 17 cm wide with a vivid olive green color and brown tentacles also thrive here. Corraline algae, an encrusting pinkish-lavender/red algae, is valued in ocean environments world wide. Notice its hard texture due to calcification.
Regulations & Safety
- Do not disturb tidal pools, marine animals, or other wildlife. If you do handle an organism (again, please don't), return it to the location that you found it. Follow Leave No Trace's Tips for Tide Pooling.
- Dress appropriately. Wear warm clothing and comfortable shoes that can get wet and still give good traction.
Check the tide predictions for the Point Reyes area to find when low tide will be on the day(s) you plan to visit. Attempt to arrive at the tidepool area at least an hour before low tide so that you have plenty of time to explore safely while the water is receding. Return no later than an hour after the tide has begun to rise.
If you have limited time, Duxbury Reef is just minutes away from the nearest parking lot. If you have more time and desire to walk for a couple miles on a beach, Sculptured Beach is about an hour's walk from the nearest parking lot.
Pets are not permitted at Sculptured Beach. Learn where pets are welcome within Point Reyes National Seashore.
Another good tidepool location just south of Point Reyes National Seashore is Duxbury Reef, located at the west end of Bolinas. Duxbury Reef is part of Agate Beach Park and managed by the Marin County Department of Parks and Open Space.
The heaviest rainfall occurs in the winter months. Come prepared for rain and drizzle to possibly last for several days. In between winter rains, it is often sunny, calm, and cool.
Most spring days are windy, especially along the coast. Expect cool temperatures in March. By late May and early June, temperatures can be quite pleasant along the coast.
Although there is very little rain during summer months, there is often dense fog throughout the day in July, August, and September. Daytime high temperatures along the shorelines of the Pacific Ocean and Drakes Bay are frequently only 16°C (60°F) cooler.
The coastal areas of Point Reyes experience some of the clearest days in late September, October, and early November. The occasional storm will start rolling through in late October, bringing clouds, wind, and rain. The strongest winds occur in November and December during occasional southerly gales.
The roads and beaches of Point Reyes National Seashore are open from 6 am to midnight.
Duxbury Reef, which is part of Agate Beach Park, is open sunrise to sunset.
The best time to go tidepooling is during a minus low tide. Check the tide predictions for the Point Reyes area to find when low tide will be on the day(s) you plan to visit. Note that not all low tides are minus tides and some low tides are not low enough for successful tidepooling. Be at the tidepool area at least an hour before low tide so that you have plenty of time to explore safely while the water is receding. Return no later than an hour after the tide has begun to rise.
Access to the intertidal area requires travel over sand, slippery rocks covered with algae, and pools of water with depths of a foot or more, depending on the tide.
Sculptured Beach is two miles from the nearest parking lot via a sandy beach. The sand above the high tide line is usually soft and loose, but the sand below the high tide line should be firmer.
The path to Duxbury Reef is a short, steep 0.1 mile dirt trail from the parking lot to the beach. An Inclusive Access trail near the parking lot overlooks the beach and reef.