Males of many species of spider engage in alternative mating tactics that do not involve pre-mating courtship. Here I report field observations of a novel opportunistic mating tactic of the wolf spider Rabidosa punctulata (Hentz, 1844): simultaneous double mating, whereby males that encounter copulating pairs also mount and achieve inseminations concurrently with the first male. On three separate occasions, female R. punctulata were observed mating with two males simultaneously. Males that mate with already copulating females likely receive multiple fitness benefits. It may allow courtship parasitism of other males while also reducing male agonistic interactions, eliminate the need to court or subdue the female, and reduce pre-mating cannibalism risk. If such behavior is common, it may limit sexual selection acting on male courtship displays by reducing the effectiveness of pre-mating female choice while also increasing sperm competition.