Can the Halo Collar be worn in the water? March 13, 2020 21:04 Yes, the Halo Collar has been through significant testing—including submersion, swim testing, and salt water testing. Related articles How often should I recharge my Halo Collar and what is the expected battery life of the collar? How is Halo different from other “smart” collars? How do I interpret the LEDs? Does Halo work with iPhone? How do I know what size strap to order?