SF Bay Swimming Primer

As more and more of you get comfortable swimming in Lake Michigan, I guarantee that you will be enticed by some of the more exotic swim events in San Francisco Bay. And you should definitely consider signing up for one (or more!) of them because they are hands down some of the coolest swim events you can do.

I field a lot of questions about swimming in SF Bay, and I’m always surprised at the level of misinformation surrounding these events. Most people seem to harbor two beliefs – namely, that SF Bay is dangerously cold and that it is infested by man-eating sharks. Both of these are false.

Regarding the latter, here’s a blurb from the Federal Bureau of Prisons site on the history of Alcatraz:

One of the many myths about Alcatraz is that it was impossible to survive a swim from the island to the mainland because of sharks. In fact, there are no “man-eating” sharks in San Francisco Bay, only small bottom-feeding sharks. The main obstacles were the cold temperature (averaging 50-55 degrees Fahrenheit), the strong currents, and the distance to shore (at least 1-1/4 miles). Prior to the Federal institution opening in 1934, a teenage girl swam to the island to prove it was possible. Fitness guru Jack LaLanne once swam to the island pulling a rowboat, and several years ago, two 10-year-old children also made the swim.

Regarding the former, yes the water in SF Bay is colder than an 80F swimming pool. But compared to Lake Michigan, it is relatively balmy for most of the year. While the SF Bay temperature rarely hits the 60F mark during the summer, the water doesn’t freeze over like it does here. Most of the time the SF Bay water temperature hovers in the 52F – 55F range, which we typically swim in on either end of the summer months (and during the winter, we swim in MUCH lower temperatures).

Just to give you an idea of what it’s like, here’s a write up for the Escape From the Rock Triathlon on what to expect during the swim:

If you find that when you jump in the water or start to swim that your heart begins to beat rapidly and your breathing feels out of control, this is perfectly normal. It’s just the adrenaline rush of race day paired with the shock of the cold bay water. Use your own judgment on whether to continue, especially if you have any medical conditions, but most people find that if they continue to swim, they warm up, get their breathing back under control and are able to get back into a groove and finish the swim. You may backstroke, or swim with your head out of the water until you’re comfortable to swim again.

Bottom line: with the proper equipment and preparation (all of which we blog about here) you can easily add a SF Bay swim to your list of endurance sports accomplishments.

The ultimate fact is that thousands of people do a Bay swim each year – and for many of these swimmers it’s their first open water experience ever. And if you still think this is something beyond your ability, let me remind you that a dog did the Alcatraz swim back in 2005 in just under 42 minutes.


  1. Suz
    August 29, 2012

    Any tips for the swim? Due to swim 9-8-12 …..

  2. LukeM3
    July 24, 2009

    So I’m sitting in my PJ bottoms, fleece top and bright orange and yellow skimpy tri suit waiting to be dropped off near Alcatraz a few weeks ago. A boat load of us are a bit nervous and striking up conversations to keep our nerves in check. Met all kinds of people from California, and felt oh so special because I came all the way from Illinois. Wouldn’t you know it, 2 people away from me on the boat is Steve from Open Water Chicago. Small world.

    To prep for Alcatraz I swam (sans wet suit) in Lake Michigan in Highland Park. The water was 56-64 degrees in the 6-7 times I swam from late June until early July. The water at Alcatraz Challenge was 60 on 7/12. So temps aren’t the issue. I jumped off the pier in HP to simulate the jump from the ferry at the start of the Alcatraz race. What I underestimated where the currents, waves, and foggy conditions. Oh and how can I forget all the salt water I snorted.

    So if a flabby old guy can make the swim (and follow up with the 7-mile run), surely you young whipper snappers in wet suits and neoprene caps can do it.

    You gotta swim Alcatraz–at least once.

  3. diver dave
    July 3, 2009

    ? ? ? did the dog wear a full wet suit ? ? ?
    i do not believe that you get an adrenaline rush which causes your panic. Perhaps cold shock which will cause your body to shut down blood flow to your arms , legs ,lungs … so the blood will stay in you heart and brain in order to try to keep you alive…

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