🏖️ Lake / Reservoir
🟢 Easy $12-15 per adult during summer season
🌊 About Boulder Reservoir
'The Rez' to locals — a sandy-beach reservoir with a dedicated, LIFEGUARDED swim area (unusual for this region), concessions, and Flatirons views.
📋 Visit Details
Entry Fee
$12-15 per adult during summer season
Water Temperature
💧 Cool-to-warm reservoir water
Best Season
📅 Summer (10am-6pm, early close 5:30pm Thursdays)
Water Type
Reservoir with lifeguarded swim beach
Managed By
City of Boulder (Boulder Reservoir)
County
Boulder County, Colorado
🗺️ Getting There
Address / Access Point:
5100 N 51st St, Boulder, CO 80301
Access Notes:
Easy, developed access with lifeguards — one of the only lifeguarded natural-water swim spots in this file
✅ Before You Go — Checklist
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Check current water conditions — especially after recent rain
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Save GPS coordinates offline before leaving — cell service may be limited
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Bring cash or card for entry: $12-15 per adult during summer season
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Pack reef-safe sunscreen, dry bag, water shoes and plenty of drinking water
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Tell someone where you are going before heading to a remote location
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Pack out everything you bring in — leave no trace