Here’s where to find Ontario’s largest natural caves with hidden blue waters

One of Ontario’s most fascinating underground attractions, Tyendinaga Cavern and Caves, is reopening for the season this month, allowing visitors to descend into ancient limestone caverns and explore hidden crystal-blue waters.

This family-run attraction takes guests deep underground into what’s considered Ontario’s largest known cavern. Adventure seekers and nature lovers alike have been flocking to the site for nearly 15 years after owners Charles and Elizabeth Koch spent decades carefully restoring and preserving the cave system.

Guests experience the caves on a guided tour lasting roughly 45 minutes, including an above-ground briefing to learn about the area’s fascinating geology and underground ecosystem before heading down into the cavern itself.

Visitors can expect to see towering limestone walls, narrow passageways, and fossil-covered rock formations, but one of the site’s most striking features is the underground wishing well, filled with crystal-clear blue water.

Tours also tap into the region’s rich geological history, highlighting fossils estimated to be 450 million years old, as well as the effects of weathering and glaciation on the landscape. It’s truly a nature nerd’s paradise.

And the adventure doesn’t stop underground.

Above ground, the 60-acre property includes walking trails to help visitors explore the area, as well as picnic spots and scenic lookout points, making it easy to turn the trip into a full afternoon adventure.

Tyendinaga Cavern and Caves officially opens for the 2026 season on May 16, with guided tours running on weekends through June before expanding to a longer summer schedule.

General admission for adults is $16, plus applicable taxes and fees. Reservations can be made through the attraction’s official website.

Tyendinaga Cavern and Caves is located at 2623 Harmony Rd. in Belleville, Ont.

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