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The Insider’s Guide to the Boulder Reservoir

It’s the ultimate vacation question: beach or mountains? Luckily, when you visit Boulder, you don’t have to choose! Okay, okay—so maybe we don’t have an ocean coastline. But Boulder does have the perfect spot to while away a day swimming, sunbathing and boating: Boulder Reservoir. Its cool, sparkling water and views of the Flatirons are hard to beat. 

Best family-friendly beach in Colorado — Lonely Planet

The 700-acre lake, often lovingly referred to as "the Rez," was initially created in the mid-1950s as a water-storage facility. But although it still supplies approximately 20 percent of Boulder’s drinking water, the lake and its surrounding environs quickly gained a reputation as one of the best spots in the state for boating, swimming, fishing and other lakeside recreation. 


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6 Things to Know About Boulder Reservoir

The Basics: The Boulder Reservoir is open year-round. Entry fees are charged during the summer season from April 1, 2024 through October 31, 2024.

  • April 1-May 23 and Sept. 3-Oct. 31: $5 per individual or $10 per carload
  • May 24-Sept. 2: $7.25 per youth (3-18 years); $12 per adult; $9 per senior (60+ years)
  • Summer twilight entry 6pm-close: $5 per individual or $10 per carload
  • There is also a 25% Sustainability Discount for pedestrians, cyclists and cars with 3 or more. Dogs aren't allowed during the summer season.
Wander Wisely

Sorry, dogs aren’t allowed in the park during the paid summer season. But you can bring your canine companion to the south shore for a dip from Labor Day to May 15.

1. Can you swim in the Boulder Reservoir?

The swim beach is open daily 10am-6pm for summer 2024 (May 24-Sept. 2). (Note: The swim area closes at 5:30pm on Thursdays). There’s something surreal about working on your tan (but be sure to wear sun protection — the sun here at altitude is no joke!) while you stare up at mountains, and it’s an experience you won’t get many places besides Boulder Reservoir. The lake boasts one of the largest swimming beaches in Colorado. Splash around with the kiddos in the shallow section, swim out to one of the three floating platforms or simply lay on your beach towel and soak up the sun. A lifeguard is on duty, and children under 13 must pass a swim test to go beyond the first rope. Note: Swimming is prohibited in the event of lightning or thunder and the beach is closed for 30 minutes after any lightning strike. 

2. Is boating allowed?

Rocky Mountain Paddleboard rents a pontoon boat by the hour, so you can spend the day sipping, sunning and fishing. Note: Annual permits are required for all outside boats; one-day permits are not available. You can also sign up for sailing classes or private lessons through Community Sailing of Colorado. The company also offers sailboat rentals, group lessons and parties, and free adaptive sailing clinics.

There is also EXPAND Beyond, an adaptive water ski program, that gives folks with physical disabilities the opportunity to hit the open water. The program operates Tuesday mornings from 8-11am in mid-June for eight weeks at the Reservoir.


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Insider Tip

On Tuesday evenings in spring, the Dash & Dine 5K series at the Rez combines a fun 5K race and a post-race dinner with a party atmosphere.

3. Can you kayak, canoe or standup paddleboard?

You have options to rent kayaks, canoes or SUPs by the hour from Rocky Mountain Paddleboard, which is located right on site at the Rez. Unless you have a permit (and they usually sell out before the season even starts), you cannot bring your own kayak, canoe or SUP to the Boulder Reservoir.

Another great option is to sign up for a lesson, where a certified instructor will teach you the basics or help you perfect your technique. Yogis can put their practice to the test with SUP (standup paddleboard) yoga classes.  


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Insider Tip

The reservoir is perfect for open-water training for triathletes practicing their swim stage. There are drop-in sessions regularly in the summer.

4. Can you fish at the Boulder Reservoir?

Yep — cast a line for bass, catfish, crappie, rainbow trout, saugeye and walleye from the fishing dock, shore or a boat. Follow the Boulder Reservoir Loop Trail for some of the best fishing access. Note: You must purchase a fishing license from Colorado Parks & Wildlife online or in person. 

Insider Tip

The water temperature in Boulder Reservoir changes daily. Call the front gate for the current water temperature: 303-441-3461.

5. Are there paths for running, walking, hiking and biking?

The park offers miles of trails for running, walking, mountain biking and hiking, including the 5.3-mile Boulder Reservoir Loop Trail. Keep an eye out for wildlife, as the park is home to geese, coots, loons, osprey, raptors, herons, owls, deer, rabbits, snakes and prairie dogs. Boulder Reservoir also plays host to a number of fitness events (click on "Special Events at the Reservoir" on the right side of the page) throughout the year, from 5K races to marathons and triathlons. And hey, what better way to cool down after a tough workout than with a dip in the lake?


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Insider Tip

Alcohol is allowed at Boulder Reservoir (except on July 4), as long as it is not in a glass container. May we suggest picking up a six pack from a local brewery? Asher Brewing Company, Avery Brewing Company, Beyond the Mountain Brewing, Finkel & Garf Brewing Company and Gunbarrel Brewing Company are just a few minutes’ drive.

6. What are the options for eating and gathering at the Boulder Reservoir?

Got something to celebrate? Or just want to get out and grill? Boulder Reservoir's park has 13 picnic sites, nine of which are available to rent for private events from late April through September. Rentals include setup and takedown of canopies, picnic and serving tables, and trash and recycling containers.

Or simply pack a picnic lunch and grab one of the many first-come-first-serve picnic tables. Sand volleyball courts and horseshoe pits will keep you and your guests entertained.

Insider Tip

The Boulder Rez is a delight in winter. It's peaceful, the panoramas are snow-dusted and spectacular, you can bring your dog, and there's usually plenty of sunshine to warm you as you stroll around the Loop Trail. Plus, entry is free between Labor Day and Memorial Day.


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