Latham’s Snipe has a characteristic and conspicuous display flight that includes power-diving and loud drumming sounds. However, the ecology of this Snipe has received little study, perhaps in part because the bird has been considered difficult to sex. We measured eight morphological traits and examined adult and juvenile birds to identify sexually dimorphic characteristics useful for sexing in the field. To confirm the sex determination, molecular sexing was also performed. Four traits in adults and juveniles showed marked differences between sexes, with males weighing less, having shorter bills and longer and more rectrices. A logistic regression model of two measurements, bill-length and number of rectrices, correctly allocated 81.9% of the sample birds to the correct sex. Sexual dimorphism in this Snipe may be a consequence of sexual selection on male agility while performing display flights.