•Time course of the reproductive activity was determined in ewes of three breeds.•Ewes were reared in the field conditions and followed over a period of 2.5 years.•General pattern of breeding season for ewes at temperate latitudes was confirmed.•Significant variations in reproductive patterns were determined between breeds. The aim of this study was to establish the time course of the annual reproductive cycle in ewes of the Jezersko-Solchava, Bovec and Istrian breeds (n=24, 8 of each breed) with various production features in the sub-Mediterranean region under field conditions. The ewes were followed over a period of 2.5 years, starting at the age of 3 months. Serum progesterone concentrations used for the evaluation of ovarian activity were measured twice monthly with a 10-day interval. The studied ewes displayed a general pattern of annual reproductive activity known for sheep breeds of moderate latitudes, correlating negatively with photoperiod (P<0.0001), but some differences were observed between them regarding puberty onset and the resumption of ovarian activity after lambing. In the Jezersko-Solchava and Bovec breeds, puberty started in the first autumn after their birth, at the average ages of 7.7±1.4 and 8.5±1.5months, respectively. The majority of the Istrian ewes entered puberty in the following autumn, at the age of 18 months, confirming the late sexual maturity of this breed. Ovarian activity continued until the early spring, lasting on average 3.9±0.6 moths in Jezersko-Solchava, 4.0±0.6months in Bovec and 3.7±0.6months in Istrian ewes. Breeding season in mature Jezersko-Solchava and Bovec ewes started in early autumn and ended rapidly with pregnancies in all studied ewes of these breeds. Spring lambing in mature Jezersko-Solchava ewes was followed by the resumption of ovarian activity in June 2011, indicating an early timing of the breeding season in this sheep breed. Pregnancies in Jezersko-Solchava ewes were confirmed from August 2011 on with a 100% pregnancy rate in October 2011. Ovarian activity was detected in August 2011 in 75% of the Bovec ewes and 100% of the Istrian ewes. In November 2011, all of the Bovec ewes were pregnant, while in Istrian ewes, pregnancy rate only reached 75%. Our results indicate important differences in the patterns of annual reproductive activity in various native sheep breeds that are bred under identical environmental and geographical conditions.