A wrist-wearable device including an outer housing with a back cover, a front cover being parallel to the back cover, and a circumferential wall therebetween, the wall being perpendicular to the back cover and to the front cover. The device further includes at least one slot antenna configured to send and to receive electromagnetic signals, the slot antenna including a case made at least partly of an electrically conducting material and being fitted in the housing of the device. The case is limited on one side by an outer face lying substantially in a common plane with the wall of the housing. A slot extending substantially in a direction perpendicular to the back cover and the front cover is formed in the outer face of the case, the inside of the case thereby forming a cavity of the slot antenna.