Normally during the off-season, between and Labor Day and Memorial Day weekends, these tours are only offered twice daily, at 10:00 and 1:00.
The Kings Palace Ranger Guided tour winds through four rooms, historically called the Scenic Rooms, of Carlsbad Cavern as the Park Ranger describes the history and geology of the features. The tour takes about one and half hours and includes a blackout, so that visitors can experience the cave as it is naturally. In addition to the general entry ticket, Kings Palace
Tickets are $8 for adults and $4 for Senior Pass cardholders and children ages 4-15; children under age 4 no allowed.
Source: Carlsbad Current-Argus