I wan thinking about getting an Apple Watch series 3 Nike +. If I connect the watch to my phone, and I'm at school and not connected to wifi but I'm connected to my phone, can I send text messages? Or if I want to do this will I have to get the cellu

Hi

All models of Apple Watch can be used to send and receive text messages when the Apple Watch is connected to the paired iPhone via Bluetooth and the iPhone has a cellular connection.

The functions that are available on your Apple Watch when it is away from your iPhone depend on various factors including:

• Your Apple Watch model:

  Apple Watch - Compare - Apple

• The features of your carrier service plan:
  • Apple Watch - Carriers - Apple
  • Make a call with Wi-Fi Calling - Apple Support
• The type of connectivity that is available to your Apple Watch at the time:
  • About Bluetooth, Wi-Fi, and cellular on your Apple Watch - Apple Support
  • Use the Control Center on your Apple Watch - Apple Support

Features and requirements that apply under various circumstances are detailed here, including within footnote #1 in respect of text messages:

How to use your Apple Watch without your iPhone nearby - Apple Support

For information and assistance regarding the features offered by third-party apps under different connectivity circumstances, I suggest that you consult the developers' support resources and/or contact them.

Unless you are onWiFi or cellular you will not be able to text.