To call a London cell phone from the USA, dial +44 7 followed by the rest of the UK mobile number. The key distinction is that UK mobile numbers start with 7 after the +44 country code, and you must drop the leading 0 that is used for domestic dialing.
How to call a London cell phone from the USA: The exact dialing sequence
The complete dialing sequence for a London mobile from the United States is +44 7... (or 011 44 7... from a landline). London cell phones are UK mobile numbers, so they use the UK mobile prefix 7 rather than the London geographic area code 20. When dialing, you always replace the domestic leading 0 with the international access code and country code. This applies whether you are using a mobile phone or a landline.
Step-by-step dialing instructions for iPhone
On an iPhone, the fastest way to dial a London mobile is to use the + key. Press and hold the 0 key on the keypad until the + symbol appears. Then enter 44 (the UK country code), followed by the mobile number without the leading 0. The complete dialing string will look like +44 7....
Apple’s Dial Assist feature can simplify this further. Dial Assist is found at Settings > Apps > Phone > Dial Assist. When enabled, it automatically determines the correct international or local prefix when you dial from your contacts or favorites. This means that if a contact is saved with a UK number, the iPhone can add the +44 prefix for you.
Step-by-step dialing instructions for Android
On an Android phone, open the Phone app and press and hold the 0 key until the + symbol appears. Then dial 44 followed by the UK mobile number without the leading 0. The complete dialing string is +44 7....
Google’s Phone app includes an Assisted dialing feature to automate this. To configure it, open the Phone app, tap More (the three-dot menu), then go to Settings > Calls > Assisted dialing. Turn on Assisted dialing and set your Default home country to the United States. When enabled, the app will automatically add the correct international prefix when you dial a number that is not in your home country.
Understanding the UK mobile number format
UK mobile numbers always start with 7 after the country code. The domestic format includes a leading 0 (e.g., 07xxx xxx xxx), but this 0 is always dropped when dialing from the USA. The international format is +44 7... (or 011 44 7... from a landline). This is the crucial distinction between UK mobile prefixes and geographic area codes: mobile numbers use the 7 prefix, while London landlines use the 20 area code.
Cost-effective ways to call London mobiles
To minimize costs, check if your carrier offers specific international plans for the UK. Google Fi includes international dialing in its standard rates, and its Wi‑Fi calling feature can reduce charges. For Google Fi, tap and hold 0 until + appears, then dial the country code and number. On Google Fi, the help page distinguishes Canada and U.S. Virgin Islands from other countries, so the UK follows the 'all other countries' rule. Wi‑Fi calling settings are available in both the iPhone Settings app and the Google Fi app (iPhone must have iOS 15.4 or higher for troubleshooting). Google Fi Wi‑Fi calling troubleshooting requires iPhone or iPad to have iOS 15.4 or higher.
Internet-based apps like WhatsApp, FaceTime, and Skype are often the cheapest option. These apps make calls over Wi‑Fi or mobile data, avoiding traditional carrier rates. Both you and the recipient need the app installed and a stable internet connection.
When researching options, understanding international calling codes and dialing (How to Dial International Phone Numbers and Country Codes) helps you compare plans. To call London from US cell phone (How To Call London From US Cell Phone) affordably, always verify your carrier’s international rates before dialing.
Frequently Asked Questions
Do I need to include the first 0 in a UK mobile number?
No. When dialing from the USA, you always omit the leading 0 that is used domestically. The international format uses +44 followed directly by the mobile number starting with 7.
What menu path turns on Apple’s automatic dialing help?
Go to Settings > Apps > Phone > Dial Assist to enable this feature. It automatically adds the correct international or local prefix when dialing contacts.
What menu path turns on Google’s dialing help?
Open the Phone app, tap More > Settings > Calls > Assisted dialing, then set your Default home country. This lets the app automatically add the international prefix for numbers outside your home country.
Can I use my USA cell phone in London without extra charges?
It depends on your carrier. Many US carriers offer international roaming plans, but charges can be high. Using Wi‑Fi calling or a local SIM card (if your phone is unlocked) are common alternatives to avoid roaming fees.
Are there time differences I should consider when calling London?
Yes. London is typically 5 to 8 hours ahead of US time zones, depending on daylight saving time. Check the current time in London before calling to avoid calling at inconvenient hours.
