A navigation system is provided for use by a snorkeler. A GPS signal receiving antenna (31) is coupled to the snorkeler in a substantially fixed spatial relationship and communicates with a display (41) to provide the snorkeler with navigational information. In the illustrative embodiment, the GPS signal receiving antenna (31) is attached to the breathing tube (23) of the diver's snorkel (20) and communicates with the display (41) of a handheld GPS receiver (40) housed in a waterproof case (50). The GPS signals received by the GPS signal receiving antenna (31) are conveyed to the handheld GPS receiver (40) via a GPS re-transmitting antenna (35) housed in the same waterproof case (50). An externally operable pushbutton (56) allows the snorkeler to switch between multiple screens presented on the display (41) to guide him through the snorkeling site.