Previously an exclusive to EE and Vodafone in the UK, you can now buy the LTE version Apple Watch as part of a contract with O2.
It'll allow you to connect the Apple Watch with your existing phone contract on O2, or if you're switching to the network it's also available on a new contract too.
An alternative provider
The Apple Watch 4 price is £14.50 a month, £20 upfront and the rolling internet plan costs £5 a month. You'll get the first six months of airtime free, but it's a 36 month contract, so you'll be paying for the next 30.
Over that three year period, this deal for the Apple Watch 4 is set to cost you £692.
The Apple Watch Series 3 is cheaper, and it has a similar deal with your first six months of airtime offered for free. The device is £9.99 a month, and its upfront cost is also £20.
Again, this is only offered on a 36 month contract, which would end up costing you just under £530 over the lifetime of the device.