Quick answer: Look for a GPS tracker with at least IP67 waterproofing — that means it survives submersion in 1 meter of water for 30 minutes, covering most real-world water exposure.
IP67 means dust-tight and submersion up to 1 meter for 30 minutes. IP68 covers deeper submersion at manufacturer-specified depth. For a dog that swims regularly, IP67 is the minimum. Don't rely on 'water resistant' labels without an IP rating — it means nothing specific.
The charging port is the most common weak point in waterproof trackers. Look for models with magnetic charging or a sealed port cover. Even IP67-rated devices can fail at the charging point if the cover is left open or wears out over time.
If your dog swims daily (Labs, Retrievers, Spaniels), look for IP68 and check user reviews specifically for real-world swim durability. IP67 covers rain and splashing reliably but repeated submersion over months can compromise cheaper builds at the seals.
Any GPS tracker used outdoors regularly should have IP67 minimum. The charging port design is the detail most buyers overlook — it's the most common point of water entry.