Welcome to Total Bottom Time!

Total Bottom Time is an online dive community where scuba divers from around the world can log their dives and share them with family, friends and other divers. People can subscribe to the dives you post via email or RSS.

Total Bottom Time (TBT) is the total amount of time a diver has spent at depth. It is the sum of the bottom times of all of a diver's dives, including residual nitrogen time.