Carlsbad Caverns Tour Schedule

The Carlsbad Caverns NPS website lists their tour schedule (along with all sorts of other sundry stuff). They do recommend that you make reservations.

Summer Tour Schedule
Tour	Time
Kings Palace	Daily 10:00, 11:00, 12:00, 2:00, 3:00
Left Hand Tunnel	Daily 9:00
Slaughter Canyon Cave	Daily 10:00
Lower Cave	Monday-Friday 1:00
Hall of the White Giant	Saturday 1:00
Spider Cave	Sunday 1:00

Summer Visitor Center Hours: 8:00 to 7:00
Natural Entrance Hours: 8:30 to 3:30
Big Room Hours: 8:30 to 5:00