Swimming in Aquatic Park

Aquatic Park Cove is a protected cove inside the San Francisco Maritime National Historical Park popular with swimmers in the Bay Area. It also happens to be GGTC's premier open water swimming spot.

  • Are there sharks? "Yes, there is marine life in San Francisco Bay including sharks, seals, and sea lions. The sharks that live in the Bay are small and hang out at the bottom of the Bay. These sharks have no interest in triathletes. The larger sharks live outside the Bay where the water is nice and salty. These larger sharks do not like nor can they survive in the brackish waters of San Francisco Bay. Seals and Sea Lions may be curious about triathletes but pose no danger." – Escape from Alcatraz
  • What is the water temperature? Check out this website for real-time information. Most triathletes prefer swimming with a wetsuit, especially in the colder months.

Swimming inside the cove

The cove is the perfect training area for open water swimming. It's large enough that even experienced swimmers can rack up as many feet as they want to; safe even for beginners; and fairly protected from rougher currents, tides, and vessel traffic.

Buoy Line Swim

A buoy line swim follows, as the name implies, the swim buoys closest to the shore. The west end of the swim (on the left side of the picture below) is marked by a slightly larger buoy swim a swimming flag on top of it. Locals tend to call this buoy "The Pizza Box" because of its square shape. This line is a great place for swimmers who have little open water experience, as it's relatively protected from tides and currents. It's close to shore, meaning that you're back on the beach within minutes if anything goes wrong. A full lap is roughly 0.35 miles (~620 yards, 560 meters) long. 


Perimeter Swim

A perimeter swim is the default "advanced" swim done by club members. It follows the sea wall, offering some views of Alcatraz and the Golden Gate Bridge at the opening of the cove. The distance swam depends on how tightly you hug the sea wall and tends to differ from swimmer to swimmer. Do not swim underneath the sea wall – there's a lot of exposed steel and concrete right below the water line that you do not want to get in touch with. Furthermore, be aware that people will fish from the sea wall, so if you get too close you might swim straight into a fishing line.

We would not recommend that inexperienced open water swimmers attempt this swim on their own. Even though it's fairly protected from currents and tides, people have gotten anxiety attacks, so you should have done it a few times with swim buddies before casually doing it on your own. 


Swimming outside the cove

⚠️ Swimming outside the cove is dangerous and should never be attempted alone or without checking tides and current conditions. Do not cross the shipping lane without boat support and contacting Vessel Traffic, both for legal and safety reasons. Do not swim outside the cove without an experienced guide.

Experienced swimmers have drowned outside the cove. Do not be one of them.

The main purpose of this section is to make you aware that swimming outside the cove is a dangerous activity that requires support and careful planning. Our recommendations align with those of the two big open water swimming clubs at Aquatic Park:

  1. Do not leave the cove without an experienced swimming buddy. 
  2. Do not leave the cove without carefully considering the tides and currents. 
  3. Do not leave the cove without having fully considered that the water can be a lot more rough immediately outside the cove.
  4. Do not pass the shipping lane without boat support and having contacted Vessel Traffic. 
  5. Leaving the cove after mid-morning means that you'll encounter boats who do not expect little swimmer heads. If a boat rides over you, you'll most likely die. Swim as if you're invisible to boats, because even with a bright cap, you most likely are.

Experienced swimmers have drowned outside the cove. But even if you manage not to drown, a multi-hour swim stuck in currents in the cold bay water is terrifying. As an example, consider Ken Mignosa's swim from 2020. He's an experienced and accomplished open water swimmer, more than capable of going out for three-hour-long swims in the open bay. In September 2020, Ken got stuck in a gyre - for nine hours. He made it back but the vast majority of our triathletes would not survive that many hours in the cold open water. 

"What an IDIOT I was! During the course of my entrapment I tried exiting in every direction - toward baker beach, toward Fort Point, toward the Warming Hut, even toward the shipping channel. Every attempt at escape ended with me getting sucked back into the gyrre. Had I been unable to break free, I would have needed rescue, but I had no way to summon the Coast Guard." (Ken, at a SERC Presentation).

Reading Tide Charts

The veterans at the Dolphin Club have compiled an excellent guide about tides, currents, and how to plan for them. Similarly, the Southend Rowing Club has an equally excellent guide. Both of these clubs have been around since the late 1800s, so they know a thing about swimming in the bay. They've been doing bay swims before the Golden Gate Bridge existed. We're mentioning this information because their care and preparation might seem like overkill, especially to notoriously invincible triathletes, but both of these clubs know how to prevent death. Your death, in fact. Follow their advice.

If you'd rather learn things from us, here's a quick "Tides and Currents 99":

  • Tides describe the water going up and down, currents describe the water moving left and right.
  • Tides are caused by gravitational forces of the moon and sun. 
  • Oceanic currents have many factors - and tides are just one of them. Wind and thermohaline circulation are also major factors. You cannot predict swim safety with a tide chart alone.
  • Currents ebbs (empties) and floods (fills up). Flooding will have the water at Aquatic Park rise, ebbing will have it sink.
  • Currents are measured in knots, a nautical measurement of speed (1 knot is ca 1.15mph). Ebbs range from 2-6 knots, floods from 1-4 knots.
  • Currents listed for the Golden Gate Bridge are not the same throughout the bay. NOAA publishes correction tables to estimate the tide/currents at various locations, but generally, you can expect:
    • Tides: High Tide and Low Tide to hit Alcatraz 15 minutes after it hits the Golden Gate
    • Currents: Subtract 20-30 minutes from the Golden Gate and halve the speed
  • Always swim "uphill". If you're leaving the cove, always make sure to swim against the current. Use tide and current charts or apps to ensure that you're swimming against the current for the entire outbound portion of your swim – and "with the current" for the entire inbound portion. In other words, make sure you're naturally swept back to the beach if you get tired.

Fort Mason Swim

We've already given you appropriate warnings above, but we'll repeat it here: Don't do this swim by yourself. If it's your first time, go with an experienced veteran and only during flood. The swim starts like a perimeter swim. Once you reach the opening, swim tight along Muni Pier until Fort Mason is directly across from you. Then, swim across to the East side of Fort Mason. At this point, some people keep on swimming to the "Gas House" (the far left building in our map below). Do not pass that line without boat support, since the marina down there is active and boaters are not expecting little swimmers to bop around in the water. 


Outside/Inside

Do not attempt this swim without a seasoned veteran, since the currents on the eastern side can be surprising and have swept people to the Bay Bridge. That said, a so-called outside/inside swim is usually a good choice for someone's first swim out of the cove.

It's a normal perimeter the wall on the eastern side of the opening. The "outside" refers to the bay side of the Breakwater, the "inside" to the beach side of the Breakwater. The pier here (Hyde St Pier) is an active, working pier, so you must take extra care to be aware of boats around you and stay close to the wall. 

The "easiest" way to perform this swim is to make sure that you're swimming against the current east - and with the current back to the beach.


Swimming at China Beach or Ocean Beach

Just don't do it outside of a well-organized swim with plenty of boat support. People die all the time. We often encourage people to think about just how safe swimming in Aquatic Park is – swimming at China Beach or Ocean Beach is not. In June, SFPD and the Coast Guard failed to reanimate a China Beach swimmer. Just a few weeks before, a seasoned 31-year old swimmer died after being caught by hypothermia in currents at Ocean Beach. 

In summary: Just don't.

No Warranties

All information here is provided without warranties or guarantees of any kind. Swimming is a dangerous activity. Follow any advice on GGTC.org at your own risk.

Golden Gate Triathlon Club is a 501(c)7 non-profit organization.

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