Overview
Quarry Lakes is the best supervised freshwater swimming in the East Bay — a former gravel quarry that became a 471-acre park built around three lakes, with a genuine sandy beach, lifeguards, and water that gets warm by mid-July. Niles Beach (Horseshoe Lake) is the family hub: sandy shore, a bathhouse with showers, and swim ropes marking safe depths. The park is cashless since 2024, so leave the cash at home and bring a card. Geese are present in numbers near the beach — this is worth knowing with toddlers.
How to Do It
The address is 2100 Isherwood Way, Fremont. Coming from 880, take the Decoto Road exit east, then follow Isherwood Way to the main entrance kiosk. Parking is $5 per vehicle, card only. On hot summer weekends the main lot fills by 10am — arriving before 9:30 gives you a stress-free entry. Gate hours during peak season (Memorial Day through Labor Day) are 6am to 8pm.
Once inside, Niles Beach is the first major destination — follow the paved path from the main lot. The sandy area is wide enough that you can spread a blanket well back from the water's edge and still watch kids easily. Swimmers who want to go chest-deep are required to take a brief swim test administered by the lifeguards and receive a colored wristband indicating they've passed. This applies to kids and adults. Plan a few minutes for this at the start — it's quick but you need to find a lifeguard station first. The swim area is bounded by ropes; kayaks and paddleboards are only permitted on the outer lake sections away from the swim beach.
Tips & Tricks
Water quality can be affected after heavy rain — East Bay Parks advises waiting at least 3 days after a rainstorm before swimming. Check the current water quality conditions on the park's website or the Swim Guide app before making the drive on an uncertain weather week. The park tests Niles Beach weekly during swim season.
The east side of the beach gets shade from mid-afternoon as the sun drops behind the trees. If the goal is a long afternoon session, stake out a spot toward that end to avoid cooking in full sun for 3 hours straight.
Kayak and paddleboard access is available on Horseshoe Lake, but rentals are not provided at the park itself — bring your own or check local outfitters. The boat launch ramp is at the south end of the park; a separate boating fee applies.
The park has a trail network that loops around the outer lakes and is mostly flat. A stroller-friendly walk before or after swimming takes about 45–60 minutes if you go most of the way around. It's a solid add-on and much less crowded than the beach area.
Weekday visits in June and early September are the sweet spot. July and August weekends are packed by noon; the vibe shifts from relaxed to crowded. On those weekends, go early or skip it.
Planning
Parking: $5 per vehicle (card only, no cash accepted). Beach access (swimming): $3 per person ages 16–61, $2 for ages 1–15, $2 for seniors 62+ or disabled, free under age 1. Dogs: $2 per dog. Gate hours Memorial Day through Labor Day: 6am–8pm. The swim beach operates with lifeguards and has specific swim hours — check the park page for current lifeguard schedules, as they vary by staffing. Bring towels, water shoes for the walk from parking to sand, sunscreen, a shade structure (umbrella or pop-up — the pavilions are first-come), and snacks. The park has vending machines but no full food service. Best months are June through September; July and August see the warmest water but the biggest crowds. Toddlers who aren't swimming yet can still get a full visit from the sand alone — the beach play area is extensive.
