Can you use iPhone se with Apple Watch series 3

Hi

Yes, you can use iPhone SE with both Apple Watch Series 3 (GPS + Cellular) and Series 3 (GPS) models, subject to the iPhone being updated to the latest version of iOS 11.x:

Update the iOS on your iPhone, iPad, or iPod touch - Apple Support

Set up your Apple Watch - Apple Support

• (iPhone SE is newer than iPhone 6, so is a compatible model.

Seyden5 wrote:

Just want to know

According to: Buy Apple Watch Series 3 - Apple

Apple Watch Series 3 (GPS) requires an iPhone 5s or later with iOS 11 or later.