A military officer in charge of the disembarkation phase of amphibious warfareOne of two US Navy amphibious beach party units:Beachmaster Unit One, based in Coronado, CaliforniaBeachmaster Unit Two, based in Little Creek, VirginiaA dominant male of some pinniped species, most often an elephant seal
In literature:
Beachmasters, a 1985 novel by Australian author Thea Astley"Beachmaster", a 2009 poem by Clive James reference