The Number 15 is one of the six "Numbers" (4 8 15 16 23 42). It is considered Sawyer's number, since Sawyer was assigned the number 15 by Jacob in his search for a successor. The number 15 has appeared in the following places.
- Number on the whiskey bottle that Sawyer and Christian drink from.
- Number of hours Boone flew to rescue his sister.
- Number of kilometers to the nearest town from the Australian farm.
- Number of the aisle the Nerf footballs are in.
- Number of years since Kate and Tom buried the time capsule until she took the flight (Assuming the flight was in 2004).
- Number of miles out to sea the raft was when they found the blip on the radar.
- Locke’s mother was born on the 15th of October.
- Shannon says she doesn't want to sit near a crying baby for the next 15 hours.
- The Tailies make their first camp after leaving the beach on Day 15.
- of people Bernard had originally to work on the S.O.S.
- Number of hours Charlie couldn't go without a fix on the plane
- In the episode S.O.S. Ana Lucia gives Jack a gun with 15 shots left.
- Number next to Sawyer's name on the ceiling wall with Jacob's candidates for succession as protector of the island.