This European Standard specifies safety requirements for construction, performance, sizing, marking and information supplied by the manufacturer for swimming aids intended to assist beginners with movement through the water while learning to swim or while learning part of a swimming stroke. It also gives methods of test for verification of these requirements. This part 1 of EN 13138 applies only to devices that are designed to be worn, to be securely attached to the body and which have either inherent buoyancy or can be inflated. It only applies to Class B devices intended to introduce the user to the range of swimming strokes. It does not apply to Class A or Class C devices, to pull buoys, swim rings, lifebuoys, buoyancy aids, lifejackets or aquatic toys.