Ant Slab Boulder stands as a striking gateway to the impressive Wild Basin bouldering scene within Rocky Mountain National Park. Positioned right beside the roadside, this tall boulder provides an accessible, no-fuss warm-up spot before you advance to the more challenging zones like Thug Roof and Boxcar Boulder. Approaching it is straightforward: just before the main parking area for the larger boulder clusters, you’ll notice a spacious pulloff on the right where Ant Slab rests in plain sight, beckoning climbers of varying skill levels to test their fingers and feet.

At an elevation of 8,373 feet, Ant Slab offers a refreshing blend of alpine crispness and accessible terrain. The rock itself is firm and dependable, supporting moves that range from moderate to more challenging, with classic problems including the welcoming Ant Slab (V2) which offers solid three-star climbing, and the more demanding Immortal Technique (V5), favored by those looking to push their limits. This approachable height and range make the boulder a perfect place for a quick session to limber up or dial in your technique before tackling the higher, longer routes found deeper in RMNP.

One of the defining traits of climbing here is the balance between ease of access and the raw beauty of the park. Despite its roadside proximity, the area holds a sense of quiet adventure—thick alpine air, occasional bird calls, and thinking about the surrounding peaks just a short hike away. It’s important to remember, however, that this is a protected environment subject to seasonal closures, particularly from February 15 to July 31 due to nesting raptors. The administration strictly enforces these closures to protect wildlife, with some trail areas around Cathedral Wall also restricted during these periods. Climbers must plan around these dates to ensure they leave no trace and respect the natural balance.

Weather in this high-altitude environment can shift quickly. Summer months provide the prime window for climbing with daytime temperatures cool enough to sustain crisp friction on the rock, though afternoon thunderstorms can roll in so timing your session for early morning is wise. Winter brings snow and ice, shutting down the bouldering but creating a breathtaking winter backdrop.

Getting to Ant Slab is simple: just head to the Wild Basin area of Rocky Mountain National Park, Colorado, and look for the unmistakable large pulloff along the road. This accessibility is a major advantage for climbers who want to combine a day of driving with light hiking and immediate climbing action without the longer approaches required elsewhere in RMNP.

For gear, a couple of quality crash pads and a spotter are recommended due to the boulder's height and exposure. While not a sprawling boulder field, the concentrated nature of the climbing here makes it easy to focus on honing individual moves.

In short, Ant Slab Boulder delivers a straightforward, satisfying climbing experience focused on the basics—solid moves on clean rock paired with stunning alpine surroundings. Whether you’re priming your muscles with Ant Slab (V2) or chasing the steeper sequences of Immortal Technique (V5), this roadside gem invites climbers to plug into Rocky Mountain’s wild energy while enjoying practical, hands-on climbing beta. Just be mindful of seasonal closures and weather shifts, and you’ll find yourself returning to this spot again and again as a reliable anchor point on your RMNP climbing adventures.