The mating system of Kentish Plovers was studied in Hungary in 1988-91. Pairs renested together after clutch failure on 11 occasions. In addition, two males and one female changed mates (sequential polygyny and polyandry) between clutches. Biparental care lasted 5.9±5.9 (s.d.) d (n = 20) from hatching to desertion, usually by the female. The duration of biparental care was not related to the sex of the deserting parent, but male-deserted broods hatched earlier than female-deserted ones. In 5 out of 11 cases when pairs renested together, they moved between breeding sites (11.8±5.8 (s.d.) km), as did all three birds who changed mates (10, 24 and 24 km). These recorded distances suggest that the low reported frequency of mate change may be more a reflection of the high level of breeding dispersal than of the rarity of mate change.