Joining system for floor panels (10, 20), comprising a female coupling recess formed in a first floor panel, said female coupling recess being adapted to receive a male coupling tongue projecting from an adjoining second floor panel in a direction perpendicular to a main floor surface plane in which the floor panels (10, 20) are laid, said male coupling tongue being provided with vertical locking means enabling a vertical snap joint interlocking engagement with a matching vertical locking means in said female coupling recess, the joining system further comprises an elasticity slot for facilitating resilient movement in said vertical snap joint interlocking engagement, wherein - the male coupling tongue being configured to be essentially resilient whereas the female coupling recess is configured to be essentially rigid and non-resilient; - the elasticity slot is located in the second floor panel, the male coupling tongue forming a side wall surface of the elasticity slot on the opposite side of the male coupling tongue with respect to the side with said vertical locking means enabling enhanced resilience upon insertion of the male coupling tongue into the female coupling recess; - an upper guiding surface is located on a side of the female coupling recess on the first panel forming an essentially non-resilient vertical guide for the male coupling tongue upon insertion thereof, limiting movement of said male coupling tongue in a horizontal direction towards a remaining, main portion of the first floor panel; - a lower guiding surface is located on an upwardly extending horizontal locking lip formed at a distal end of the female coupling recess with respect to the remaining, main portion of the first floor panel, said lower guiding surface forcing the male coupling tongue to resiliently deflect whilst in engagement with said upper guiding surface upon further vertical insertion thereof in a curved J-shaped deflection movement towards said remaining, main portion of the first floor panel, the vertical locking means of the male coupling tongue snaps together with the matching vertical locking means of the female coupling recess, wherein - said lower guiding surface at its lowest end transitions into an essentially vertically extending horizontal locking surface exerting a horizontal pressure on the male coupling tongue in a horizontal direction towards a remaining, main portion of the first floor panel, holding the vertical locking means (50,60) in engagement with each other in a fitted state between the first floor panel and the second floor panel. - the male coupling tongue being configured to be essentially resilient whereas the female coupling recess is configured to be essentially rigid and non-resilient; - the elasticity slot is located in the second floor panel, the male coupling tongue forming a side wall surface of the elasticity slot on the opposite side of the male coupling tongue with respect to the side with said vertical locking means enabling enhanced resilience upon insertion of the male coupling tongue into the female coupling recess; - an upper guiding surface is located on a side of the female coupling recess on the first panel forming an essentially non-resilient vertical guide for the male coupling tongue upon insertion thereof, limiting movement of said male coupling tongue in a horizontal direction towards a remaining, main portion of the first floor panel; - a lower guiding surface is located on an upwardly extending horizontal locking lip formed at a distal end of the female coupling recess with respect to the remaining, main portion of the first floor panel, said lower guiding surface forcing the male coupling tongue to resiliently deflect whilst in engagement with said upper guiding surface upon further vertical insertion thereof in a curved J-shaped deflection movement towards said remaining, main portion of the first floor panel, the vertical locking means of the male coupling tongue snaps together with the matching vertical locking means of the female coupling recess, wherein - said lower guiding surface at its lowest end transitions into an essentially vertically extending horizontal locking surface exerting a horizontal pressure on the male coupling tongue in a horizontal direction towards a remaining, main portion of the first floor panel, holding the vertical locking means (50,60) in engagement with each other in a fitted state between the first floor panel and the second floor panel.