Which Smartwatch Should You Buy? Check Which Phone You Have First

A smartwatch doesn't work on its own. It connects to a phone, and not every watch connects to every phone. So before you choose a color or a screen size, the first question is which phone you have.

Smartwatch for iPhone, for Android, or for both

Apple Watch connects only to an iPhone. According to the spec page, the Apple Watch SE 3 and Series 11 require an iPhone 11 or later (or a second-generation iPhone SE or later) with iOS 26. If you're looking for a smartwatch for Android, look at other models.

Xiaomi is the interesting case. The Xiaomi Smart Band 10, Watch S4 and Redmi Watch 6 connect to both Android 8.0 and iOS 14 and later. In a home with both an iPhone and a Samsung, that's a watch that passes between family members without a problem. There is one exception: the Xiaomi Watch 5 page states explicitly "iOS devices are not supported."

Smartwatch with a SIM (eSIM) or Bluetooth

Many models are sold in two versions. The Apple Watch SE 3 comes in GPS and eSIM versions, and the Galaxy Watch 8 comes in BT and eSIM. The Bluetooth version receives calls and messages only when the phone is nearby. The eSIM version connects to the network on its own, so you can go out for a run and leave the phone at home.

The eSIM requires a plan from your mobile carrier, so ask whether it supports the watch before you buy. If your phone is always in your pocket, you can skip this version.

Smartwatch with payments: NFC alone isn't enough

An NFC chip in the watch doesn't yet mean you can pay with it at the register. The Apple Watch lists "Apple Pay supported," and the Xiaomi Watch 5 lists Google Wallet support. By contrast, the Xiaomi Watch S4 and Watch S5 have NFC, and their page says "no wireless payment services." If you're buying a watch for payments, look for that line, and not only the word NFC.

Water resistance, and how many days without charging

"Water resistant" doesn't mean the same thing on every page. On Xiaomi watches it says 5 atmospheres, and right after that: "not intended for hot showers, saunas, water sports and diving." The Apple Watch lists resistance up to 50 meters, and the Ultra 3 up to 100 meters.

On battery life, the bands win. The Smart Band 10 lists up to about 21 days with regular use, and 8 days with intensive use. For Apple Watch and Galaxy Watch models, the battery is listed in milliamp-hours or not at all, rather than in days, so you can't compare them directly.

Before you choose a model, open its page and look at the "system requirements" or "compatibility" line. That line decides whether the watch will connect to your phone.