Arch Rock
Anacapa Island · Channel Islands National Park · California
Visibility Breakdown
Visibility by position
Solid = diver report · outlined = today's forecast
Post Break: The range past where any waves are forming, where the water starts to have a significant increase in visibility. There might be some sediment here, but swell energy is diffused and the water is calmer.
Open Water: This zone is far out enough from the shore that the water is at its clearest. It’s deep enough that sediment is not disturbed by the wave energy at the surface. Haze can sit near the surface, so the water is usually clearer the deeper you go.
Through the day
Today's visibility readings at this spot, shown at the hour each one was taken.
Every bar is a reading for the Post Break zone.
This chart shows measured diver reports only.
Did you dive today?Please share the visibility to make our algorithm more accurate.
Report visibility
Why it reads 42 ft
Today's forecast runs
The clarity holds through the day, with a light afternoon onshore the only disturbance to the entry shallows.
High confidence
7-Day Forecast
Today is the live headline above. Tomorrow onward is the algorithm's forecast from predicted swell, wind, and rain, updated each morning and at 6 PM Pacific.
Map and parking
Channel Islands National Park · California
There is no car parking on Anacapa. Access is by Island Packers ferry from Ventura Harbor, about a one hour crossing. The ferry lands at a concrete dock at the east end of East Anacapa, with a long metal ladder up to the dock from sea level. Divers and kayakers stage gear on the dock and enter the water from the ladder.
Google Maps ↗
Apple Maps ↗
See the offshore water on Pelagiscape →Clarity, temperature breaks and kelp off this beach.
About Arch Rock
Arch Rock is the forty-foot sea arch at the east end of East Anacapa Island, the most photographed landmark in Channel Islands National Park and a longtime symbol of the park. The dive sits right beneath it, the only practical shore-entry site in the park outside of Santa Cruz. The Island Packers ferry from Ventura Harbor lands at a concrete pier near the arch, and a long metal ladder descends from the dock to the water about ten to fifteen feet below depending on tide. Divers and snorkelers stage gear on the dock, climb down the ladder, and swim out into a kelp bed that drops from a cobble shoreline to a sand floor at sixty feet. An underwater swim-through arch lies thirty to fifty yards east of the landing, tall enough for a diver in the middle, with shallow reef and kelp on either side, and divers usually cover both the landing kelp and the swim-through in a single dive.
Biomes here
Species found here
Researched habitat and range candidates. A listed species may be seasonal or depth-limited; this is not a confirmed sighting at this location.
Surf Zone
Ocean Oracle ProGain the Power
of the Oracle.
Ocean Oracle sees the future. Get 7-day visibility forecasts for every beach, alerts when a prime day is coming, and a dive log that remembers every dive.
Free shows you what the ocean looks like today. Ocean Oracle shows you the week ahead, watches your beaches for you, and remembers every dive.
One full-screen map of the water off all of California: satellite water clarity and temperature, temperature breaks, seafloor shading, depth lines, surface kelp, Marine Protected Areas, currents, wind, and swell. Save your spots as pins and get an email when a temperature break comes near them.
Visibility predictions for the entire week ahead at any beach. Plan dives, schedule charters, and book trips without guessing.
When a beach on your watchlist is running good water, or the week ahead shows a good day coming, Ocean Oracle emails you. A prime window never slips past.
Every entry freezes that day's report: visibility, tide, swell, wind. Log catches, stamp Personal Bests, level up your guns, and light up your species life list.
The Coastal Bulletin greets members with the clearest water on the coast today and their own watchlist, before a single click.
Track your favorite beaches in one place. Forecasts and alerts for everywhere you dive.
A members-only board on every beach where taking fish is legal: how other members hunt the spot, with the gear, tide, season, and target species. Post your own and earn XP.
See the future. Dive on the right days.