Blue Hole

A spring-fed blue circle interrupts the high desert just off Route 66. Blue Hole is roughly 80 feet wide and 80 feet deep at the surface, widening below, with clear water that stays near 62°F year-round. That geometry makes it both an extraordinary roadside sight and one of the country’s best-known inland scuba-training sites. Walk the rim first and watch the color shift with the light; enter the water only if current rules, your health, and your ability make it safe. Santa Rosa’s 2026 visitor information currently lists swimming hours Monday–Friday 10:00 a.m.–7:00 p.m. and weekends noon–7:00 p.m., with early hours reserved for certified divers, but it explicitly says to call for updates. There is no lifeguard. Diving requires identification, current certification, sign-in, and a paid permit; vehicle parking also requires a permit. Check conditions before arrival, obey capacity limits and every closure, never enter sealed cave passages, and do not mix alcohol or cannabis with water access. A photograph from the rim is the complete Hop; swimming or diving is optional and never implied. More

A spring-fed blue circle interrupts the high desert just off Route 66. Blue Hole is roughly 80 feet wide and 80 feet deep at the surface, widening below, with clear water that stays near 62°F year-round. That geometry makes it both an extraordinary roadside sight and one of the country’s best-known inland scuba-training sites. Walk the rim first and watch the color shift with the light; enter the water only if current rules, your health, and your ability make it safe. Santa Rosa’s 2026 visitor information currently lists swimming hours Monday–Friday 10:00 a.m.–7:00 p.m. and weekends noon–7:00 p.m., with early hours reserved for certified divers, but it explicitly says to call for updates. There is no lifeguard. Diving requires identification, current certification, sign-in, and a paid permit; vehicle parking also requires a permit. Check conditions before arrival, obey capacity limits and every closure, never enter sealed cave passages, and do not mix alcohol or cannabis with water access. A photograph from the rim is the complete Hop; swimming or diving is optional and never implied. More