Hi
Upgrading your Apple Watch
Apple Watch Series 3 (GPS) cannot be upgraded to add support for the built-in cellular feature that is supported on Apple Watch Series 3 (GPS + Cellular) models and Apple does not currently accept Series 3 models under its trade-in program:
Subject to its return policies, Apple only accepts products for exchange or refund that have been purchased directly from Apple. For an Apple Watch that has been purchased directly from Apple, Apple's Standard Return Policy varies by country, but is typically 14 days. More information and instructions for returning an item are available here (for the US, for example):
Returns & Refunds - Shopping Help - Apple
If you need help with return options, then contact Apple (in the US, for example):
Contact - How to Contact Us - Apple
If you are in a different country, then check the corresponding page for your location.
Other retailers' return policies may vary.
Features
All models of Apple Watch - including Series 3 (GPS) - include support for connecting to compatible Wi-Fi networks as a fallback when the Bluetooth connection to the paired iPhone is unavailable.
Your Apple Watch also supports many other features, including sending and receiving texts, making and receiving calls and many other features when your paired iPhone is nearby and connected to a cellular network and, potentially, also under other certain other circumstances (see below):
As you know, Apple Watch Series 3 (GPS) models do not have a built-in cellular capability. Any calls or data-related services are routed either via the paired iPhone or via a direct connection between the watch and a compatible Wi-Fi network (when the watch cannot connect to the paired iPhone via Bluetooth).
Specific support for the watch is not required on the cellular plan for the paired iPhone. Apple Watch Series 3 (GPS) can be used in conjunction with an iPhone 5s or newer model of iPhone (running the latest version of iOS) and a service plan for the iPhone from any carrier.
The fullest range of features is available when your Apple Watch and the paired iPhone are connected via Bluetooth and your iPhone has access to both cellular service and the Internet (via either cellular data or Wi-Fi).
You do not necessarily need to have your iPhone on or immediately around you (within arm's reach, for example) for the devices to establish and maintain their Bluetooth connection. Normal Bluetooth range is around 33 feet / 10 meters (this will vary in practice due to wireless interference).
Whenever your watch cannot connect to the iPhone via Bluetooth, it will attempt, as a fallback, to connect to a known Wi-Fi network - this being a compatible 802.11b/g/n 2.4GHz Wi-Fi network (some exceptions apply) that your iPhone has connected to before whilst your Apple Watch was connected to the iPhone via Bluetooth.
When instead connected to Wi-Fi, the watch also still offers a number of features, including receiving and sending messages via iMessage. If your carrier offers Wi-Fi Calling and it is supported on your plan and enabled on your iPhone, you can also use Apple Watch to make calls and (subject to carrier support) to send and receive SMS / text messages.
If your Apple Watch is unable to connect either via Bluetooth or Wi-Fi, it again still offers some - although fewer - features.
Features that are available in each case are detailed here:
How to use your Apple Watch without your iPhone nearby - Apple Support
For the best performance from your iPhone and Apple Watch, including the most power-efficient communication between them, Apple recommends keeping both Bluetooth and Wi-Fi permanently enabled on your iPhone.
More information:
About Bluetooth and Wi-Fi on Apple Watch - Apple Support
Make a call with Wi-Fi Calling - Apple Support
Make calls over Wi-Fi
Getting to know your Apple Watch
Resources for learning about and configuring your Apple Watch include:
Apple Watch User Guide:
Support articles:
Free workshops at Apple Retail Stores:
Personal setup
- If you bought your Apple Watch from Apple (whether online, by phone or in an Apple Store), then you may wish to take advantage of a free Personal Setup session (refer to Apple's related email to schedule this).
- Personal Setup can help with answering questions, explaining key features, helping you to find apps and showing you how to personalise your Apple Watch.
- Apple Store - Personal Setup - Apple
If you are still within the period, then you can also take advantage of your initial 90 days of complimentary telephone-based technical support. Contact options for Apple include: