[3] Her dam Here's To You was a descendant of the American broodmare Warrior Lass, making her a distant relative of Bounding Home and Riva Ridge.
The ground was heavy again on 13 June when Harbour was one of fourteen fillies to contest the Prix de Diane over 2100 m at Chantilly Racecourse.
She was made 6/5 favourite, with her main opposition expected to come from River Lady, who had been an impressive winner of the Poule d'Essai des Poulains.
On 3 October, racing on her favoured soft ground, Harbour started the 6.25/1 third favourite for the Arc behind the three-year-old colts Assert and Bon Sang.
[5] In the following season, Timeform's rating of 129 made Harbour their fourth best three-year-old filly behind Akiyda, Time Charter and Awaasif.
In the official International Classification she was rated the second-best three-year-old filly (behind Akiyda) and the tenth-best horse of any age or sex in Europe.