Before you start

An unlocked handset, or one that supports eSIM
A Portsmouth address, for a contract or broadband
A UK bank account, for a contract Direct Debit

Step-by-step

1
Buy a pay-as-you-go SIM or activate an eSIM on arrival
Sold in supermarkets, phone shops and online with no identity registration at all. A UK number in your first hour unlocks bank verification, NHS appointment systems and delivery notifications, all of which assume you have one.
In personWho: YouDay 1
2
Do not attempt a 24-month contract in your first weeks
Contracts run a credit check and require a UK bank account and address. With no UK credit file you will be declined or asked for a deposit. Rolling one-month SIM-only plans have no credit check and are excellent value.
OnlineWho: You
3
Take a SIM-only plan and buy the handset separately
A rolling SIM-only plan with a large data allowance costs a fraction of a bundled handset contract over the same period and can be switched monthly. Buying the phone outright is almost always cheaper in total.
OnlineWho: You
4
Keep your number when you switch
Text PAC to 65075 and you receive a porting authorisation code by return, valid for 30 days. Ofcom rules require the switch to complete in one working day. Never cancel the old service first — that is how people lose the number.
Mobile appWho: You
5
Ask what is wired into the flat, not what the postcode checker promises
A very large share of Portsmouth's rental stock is a floor of a Victorian terrace, often subdivided more than once. Full fibre reaching the street does not mean there is a fibre termination behind your door, and in a converted house an installation may need the freeholder's or landlord's consent. Ask the previous tenant what speed they actually got.
OnlineWho: You
6
Order broadband the day you have an address
UK installation takes one to three weeks and may need an engineer visit. If you work from home, treat this as the first thing you arrange after the keys, not the last.
OnlineWho: You

Documents you’ll need

Nothing at all for pay-as-you-go
A Portsmouth address and bank details, for a contract
Passport, occasionally requested for a contract

Things most newcomers don’t know

The bottleneck in Portsmouth is the building, not the network.

The city is dense Victorian terraces, an unusually high proportion of them converted into flats, bedsits and licensed share houses. Fibre in the street does not mean fibre at your door, and in a conversion the landlord or freeholder has to agree to the installation. Ask what the previous tenant actually got rather than what the coverage checker says is available.

Source: Ofcom — broadband coverage checker

The UK has no SIM registration, unlike most of Europe.

Germany, Spain and France all require identity verification to activate a SIM. The UK requires nothing for pay-as-you-go, so a working UK number is a fifteen-minute errand rather than a first-week project.

Source: Ofcom

Text PAC to 65075 — switching keeps your number in one working day.

Ofcom requires networks to issue a porting authorisation code by text on request and complete the switch within one working day. Most people never learn the shortcode and stay on an expired contract tariff for years, which is exactly what the networks are counting on.

Source: Ofcom — switching mobile provider

Check coverage on the water if any part of your life crosses the Solent.

Commuting or visiting across to Gosport, Hayling or the Isle of Wight puts you on a boat several times a week, and mobile coverage on the Solent varies by network far more than it does on land. Ask people who make the crossing daily which network they use before you sign anything.

Source: Ofcom — mobile coverage checker

Common mistakes to avoid

Signing a 24-month handset contract in your first weeks and being declined or asked for a deposit.
Cancelling the old service before requesting a PAC code, and losing the number.
Assuming street-level fibre availability means the converted flat can actually get it.
Leaving the broadband order until after you move, when installation takes weeks.
Not knowing that pay-as-you-go requires no identity check at all.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.