An adjustable length sport pole and coupling mechanism is shown and described. In one embodiment, the sport pole has a first pole assembly having a first pole and a sleeve, a second pole slidably received within the first pole assembly and a locking assembly. The second pole may have an outer surface with detents at defined locations along the pole axis. The locking assembly has a resilient locking element configured to contact and extend around an exterior portion of the second pole, and a collar movably coupled to the first pole assembly to move between a lock position and a release position. The resilient locking element extends around the second pole, and the locking element is configured so that it expands when it is attached to the second pole. The resilient locking element accordingly presses against the second pole. The collar has a retaining surface that aligns with the locking element in the lock position to hold the locking element in one of the detents to prevent axial movement between the first and second poles. The collar also has a recessed surface that aligns with the locking element in the release position to allow the locking element to disengage from the detent for permitting axial movement between the first and second poles.