Opal Pool

Overview

Tucked along the Midway Geyser Basin boardwalk, Opal Pool is a hot spring that’s actually a geyser—just a very shy one. Its appeal is the crystalline, gem-blue water you can admire up close from the boardwalk, with the occasional (and unpredictable) eruption a few times a year. Some years it doesn’t erupt at all, so come for the color and textures, not the show.

What You'll See

Expect a clear, blue pool bordered by pale sinter, with a water temperature that can reach around 132°F (56°C). It’s one of the basin’s key features and a quick stop as you loop the boardwalk. The name fits: on calm days the water looks like polished stone.

Getting There & Amenities

Access Opal Pool from the Midway Geyser Basin parking area on the Grand Loop Road between Madison Junction and Old Faithful. The same lot that serves Grand Prismatic Spring also serves this boardwalk. Restrooms are available at the parking area. Services like food and broader facilities are at nearby hubs such as Old Faithful and Madison.

Safety Essentials

This is a hydrothermal area—stick to the boardwalks and designated trails. People have suffered fatal burns in Yellowstone after entering or falling into hot springs, so supervise kids closely and never step off the walkway. No swimming, wading, or bathing. Pets aren’t allowed on boardwalks; only trained service dogs are permitted.

Wildlife

Bison and bears roam this area of the park. Give all wildlife plenty of space and never block their path on the boardwalk or road.

Best Time to Visit

Parking at Midway Geyser Basin is notorious after late morning in summer. Aim to arrive before 10:30 AM to avoid 20–30 minute waits for a spot. Don’t plan your stop around a potential eruption—the timing is sporadic at best.