The strap has a deploying clasp arranged with an articulated assembly of three elements e.g. lower clasp element (6), an intermediate clasp element (7) and upper clasp element. The clasp includes a length adjusting unit for allowing a user of the strap to adjust the length of the strap. The upper element includes an adjusting unit to adjust a longitudinal position of an end of the strap with respect to the clasp. A strap portion is fixed to the lower element via another end of the strap. Another portion is fixed to the upper element via the former end of the strap. The upper clasp element is in form of a case (13) in which a slider (14) is mounted. The watch strap is made of leather, metal or plastic.
