Apple Watch Series 5 requires iPhone 6s or later with iOS 13 or later. Wireless service plan required for cellular service. Apple Watch and iPhone service provider must be the same. Not all service providers support business accounts; check with your employer and service provider. Roaming is not available outside your network coverage area. Contact your service provider for more details. Check apple.com/sg/watch/cellular for participating network providers and eligibility.
Apple Watch Series 5 has a water resistance rating of 50 metres under ISO standard 22810:2010. This means that it may be used for shallow-water activities like swimming in a pool or ocean. However, Apple Watch Series 5 should not be used for scuba diving, waterskiing or other activities involving high-velocity water or submersion below shallow depth.