Attention all urban swim folk: SF has a bunch of nice indoor and outdoor pools hidden away, both public and private, for your fitness and pleasure. First off, if you're going to swim in the public pools of San Francisco, you need to get yourself to the McLaren Lodge Annex at 501 Stanyan Street or to the Treasurer's Office at City Hall and buy a 10-pack of pool pass scrips for $51. I don't like the word "scrip" any more than you do, but this is a slightly cheaper, more stream-lined way to use the public pools of San Francisco. Alternately, you can pay $7 cash to use SF's public pools, but you've got to have exact change. Not all of the pools mentioned here require the scrips (ugh), but if you truly want to enjoy all that SF aquatics have to offer, they will come in handy. With that said, let's (...wait for it...) dive in and discuss our favorites.

Mission Pool: Mission Pool is the best public pool in San Francisco, but don't tell anyone because no one likes a crowded pool. The facility on 19th (at Valencia) was shut down for the winter and has emerged bright, shiny, and surprisingly clean for a public space. Mission Pool is one of the few outdoor public pools in San Francisco, and the fresh air makes all the difference in the quality of your swim. Check the Rec & Parks website for lap times and arrive right when each begins. 30-minutes into any lap session, the lanes fill up with people who think they're training for the Senior Olympics.
19th Street at Linda

Hamilton Pool: Hamilton Pool makes this list (and most San Francisco pool lists) because it has waterslides. And other than driving yourself and your swimsuit to some suburban waterpark next to a gun store, or breaking into a backyard in Walnut Creek, this is the only place nearby you're going to find a waterslide. Actually, at Hamilton Pool, you'll find two. Other than the aforementioned slides, the pool and lap schedule is pretty standard for SF Rec & Parks, but SF Rec & Parks has a pretty great aquatics program. So lucky you!
Geary & Steiner

Crunch Gym at Yerba Buena: Here at SFist, we're partial to an outdoor pool, and Crunch's roof contains one of the few outdoor pools located at a gym. Formerly Club One, this current Crunch gym has a surprisingly luxurious, hotel-esque rooftop pool. All you have to do is fill out some form on their website for a "Free Day at Crunch." Otherwise, access to this terrific pool requires a gym membership, but the pool is so good that even if you hate gyms, it's worth the monthly membership for a serious swim fan.
350 Third Street

Nob Hill Spa: Fancy pants types will love the five-star indoor pool at the Nob Hill Spa, inside the gorgeous Scarlet Huntington Hotel. The pool is a bit on the small side, but the stunning outdoor deck with a view of downtown San Francisco more than makes up for it, as does the pool chair drink delivery and plush, steal-able towels. A pop into the "Zen Room" is a particularly relaxing post-swim experience, complete with potted orchids and a stack of magazines. The spa is free to guests of the hotel, spa clients, and anyone willing to pay $50 for a day pass on Mon-Thurs.
1075 California Street at Taylor

Chinatown YMCA: She's big, she's beautiful, and she is located really close to your office. This downtown YMCA has recently been so fantastically renovated, the Village People should write a whole new wedding DJ song about it. If you join the YMCA, you can use any of the other facilities in the San Francisco YMCA (including Marin and San Mateo) for $5. You can also apply for financial assistance, allowing anyone who wants to enjoy this great pool. Otherwise, day passes are $15.
855 Sacramento Street between Stockton and Grant

Fitness SF Fillmore: Double-wide takes on a whole new meaning at Fitness SF's Fillmore location, where five massive lap lanes allow for a big butterfly stroke or easy passing, depending on your workout. This facility also houses one of the largest saline-based pools in San Francisco, if saline is super important to you. Many urban gyms tend to advertise a pool, but the reality is a small, smelly puddle towards the toilets. Fitness SF has put their money where their water is, and devoted some serious resources to their pool. Other than signing up for a free three-day trial online, use of the pool requires a membership and group aquatic classes come with an additional fee.
Fillmore Center, Fillmore Street at O'Farrell

(Bonus) Fairmont San Jose: There's only one good thing about San Jose, and it's their abundance of fantastic hotel swimming pools. We've got lots of favorites, but the Fairmont's rooftop pool and lounge area is wonderful, in a San Jose kinda way. Sun-soaked and only slightly-upscale, this huge pool area is home to table service and tramp stamps. If you're looking for a pool-themed weekend getaway, grab a deal at the Fairmont, spend all day at the pool, and all night at like, a Dave and Buster's.

Hamilton Pool (photo: Katherine M/Yelp)