Polyamide with elastane for stretch and hold.

Rinse straight after swimming. Cold water to remove salt, chlorine and sun cream, which break down the stretch over time.
Wash cold on a gentle cycle. A mild detergent, no fabric softener, and wash inside out to protect the print.
Dry in the shade. Lay flat or hang out of direct sun. Never tumble dry, which shortens the life of the stretch.
No iron needed. Lycra does not need it, and heat damages the fibre.

The bottle for it

Made for this fibre, by a textile care specialist in Mönchengladbach.

For what this fibre is and where it is made, see Lycra in Materials.