With its hilly terrain and plethora of green spaces, it’s almost like San Francisco was designed for keeping fit.

Not only are there trails for hiking, steep steps for running, beautiful bike routes, and an endless expanse of water for swimming, kayaking and paddle boarding, almost all of it is 100 percent free. So ditch the pricey gym. These eight SF spots are perfect for an outdoor workout.

SF Bay is an epic place for a dip.(Courtesy of @odyssey_openwaterswimming)

Take an open water swim.

There’s no more majestic place for an open water swim than in the shadow of Alcatraz. But even if you’re not yet strong enough for the two-mile round trip, taking a more reasonable plunge into the frigid SF Bay has myriad benefits, from burning calories to improving circulation and reducing stress. Swimmers of all skill levels can launch from Aquatic Park Cove (499 Jefferson St., Marina) next to Fort Mason, but don’t attempt to reach the prison on your own. May through November, advanced open water swimmers can join the Odyssey Open Water for their monthly Alcatraz Swim.

Strength train on the Marina Green.

Hitting the gym isn’t the only way to work your muscles. The Marina’s Outdoor Fitness Station (1415 Bay St.) has the equipment you need to lunge, squat, pull, and press your way to strength. Completely free and accessible 24 hours a day, the blue-and-gray open-air gym even has diagrams to guide you through a full body circuit. Add a stop here on your bike ride through Crissy Field and across the bridge for a complete, kick-ass workout.

Swing dance in Golden Gate Park.

For almost 30 years, Golden Gate Park has played host to a longstanding SF tradition: Lindy in the Park (8th Ave. at Fulton St.). The free dance party jitterbugs and swings near the de Young Museum every Sunday afternoon from 11am to 2pm (weather permitting). You don’t need a partner or any lindy hop experience to join in (though they do offer newbies a 30 minute lesson at noon), just a good attitude and the drive to dance it out.

Glen Canyon is the perfect place for a hike in San Francisco.(Courtesy of @jsuh3192)

Hike Glen Canyon

Glen Canyon (Elk St. at Chenery St., Glen Park), a dramatic, craggy open space on the city’s southern side, is one of San Francisco’s quieter parks—and the perfect place for a hike. With close to 70 acres criss-crossed by steep trails and a lush riverine corridor, the park has the kind of terrain (and views) that will get your heart pumping. Do the entire network of interlaced trails for a solid 3.7-mile hike.

Rent a kayak or SUP and paddle the bay.

You’ll get a new perspective on the waterfront when you rent a kayak or SUP from City Kayak (Pier 40, South Beach) or Dogpatch Paddle (560 18th St., Dogpatch). At both companies, you can pick up all the gear you’ll need for a few hours powering around the bay past landmarks like Giants Stadium, the Bay Bridge, and the Ferry Building. Paddle as leisurely as you want; just 60 minutes on the water will burn off breakfast.

Run the Lyon Street Steps.

One of the best things about SF’s iconic hills is how easy it makes working up a sweat. But if you’re really craving a workout, it’s the Lyon Street Steps (2990-2996 Lyon St. at Broadway), a steep set of 244 stairs that stretch from Pac Heights to Cow Hollow, you want. Since the steps can get busy at peak (pre-work and post-work) hours, try to hit them midday or after dark. No matter what time you go, the views will be spectacular.

Biking across the Golden Gate Bridge is one of the most popular tourist activities.(Courtesy of @hannoulia)

Ride across the Golden Gate Bridge.

There’s a reason biking across the Golden Gate Bridge is one of the most popular tourist activities in the city. With views that sweep across the Marin Headlands, the Pacific Coast, and San Francisco itself, it’s arguably one of the country’s most beautiful rides. Pick the distance that suits you best—a ride across the bridge and back is just over four miles round-trip and you can add extra mileage on trails around Crissy Field, Fort Point, and Sausalito. If you don’t have a bike of your own, rent one from Sports Basement in the Presidio (610 Old Mason St.) or Golden Gate Bridge Bike Rentals in the Marina (2157 Lombard St.).

Hike at Lands End.

Often considered the most visually stunning hike in SF, trekking across Lands End isn’t just a workout, it’s a journey. The Lands End Trail (Merrie Way, Outer Richmond) loops three miles from the Presidio to the coast and back again, but if you’ve got extra energy, add in some (or all!) of the route’s nine short detours, which include Sutro Baths, Point Lobos, and Battery Chester. Combine them all for a total hike just under five miles long.