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Travel connectivity guide

Using an eSIM in the United Kingdom

How to prepare, activate and use an eSIM in the United Kingdom. Practical steps on device compatibility, choosing a Roam Star plan, daily limits and useful tips for travellers.

By Roam Star travel team

Before you travel

  • Check that your device supports eSIM and is network-unlocked. Consult your device manufacturer or the current carrier if you’re unsure; not all phones or tablets support eSIM.
  • Make a note of your current physical SIM settings and keep the original SIM in a safe place. You may want it back if you need to use your home number.
  • Back up any important contacts or two-factor authentication settings tied to your physical SIM before removing it.

Choosing a plan (Roam Star options)

Roam Star offers a range of United Kingdom eSIM plans. Pick one based on how long you’re staying and how much daily or total data you expect to use:

  • Fixed data, multiple durations:
  • United Kingdom 50GB 30Days
  • United Kingdom 20GB 30Days
  • United Kingdom 10GB 30Days
  • United Kingdom 5GB 30Days
  • United Kingdom 3GB 30Days
  • United Kingdom 3GB 15Days
  • United Kingdom 1GB 7Days
  • United Kingdom 100MB 7Days
  • United Kingdom 500MB 7Days
  • United Kingdom 500MB/Day
  • Daily allowance plans:
  • United Kingdom 2GB/Day
  • United Kingdom 5GB/Day
  • United Kingdom 10GB/Day
  • United Kingdom 2GB/Day FUP1Mbps
  • United Kingdom 1GB/Day FUP1Mbps
  • “Unlimited” with daily high-speed allowance then throttled data:
  • United Kingdom Unlimited 7 Days · 3GB/Day
  • United Kingdom Unlimited 14 Days · 3GB/Day
  • United Kingdom Unlimited 21 Days · 3GB/Day
  • United Kingdom Unlimited 30 Days · 3GB/Day
  • Long-stay option:
  • United Kingdom 50GB 180Days

Read the plan descriptions carefully: some daily plans include a fair use policy (FUP) or state that after the daily high-speed allowance you get reduced-speed data (the plan text indicates a 1 Mbps fallback where applicable).

Installing and activating an eSIM

  • You’ll usually receive a QR code or an activation code after purchase. Keep that email or QR available on a separate device if possible.
  • Typical steps (may vary by device and OS):
  • Open the mobile/cellular settings on your device.
  • Choose the option to add a mobile plan / add eSIM and scan the QR or enter the activation code.
  • Label the plan so you can tell it apart from your home SIM (e.g. "UK eSIM").
  • Set which line you want to use for mobile data, calls and SMS. If you want to keep your home number active for receiving messages, keep that SIM set for calls/SMS and use the eSIM for data.
  • Turn on data roaming for the eSIM if required by your device settings.
  • After activation, check mobile data, and try a quick web lookup to confirm connectivity. If data does not work, restart the device and check the plan is selected for data.

Using your eSIM in the UK

  • Public Wi‑Fi is common in cafés, hotels and transport hubs. Use secure connections and a VPN for sensitive tasks.
  • If you have a daily allowance plan, be aware the allowance usually resets each calendar day (check the exact reset rule for the plan you bought).
  • For plans that describe a fallback speed (for example FUP1Mbps or “unlimited then up to 1 Mbps”), expect reduced performance for high-bandwidth activities after the daily allowance is used.
  • If you need a UK phone number for local services, confirm whether your chosen eSIM plan includes voice/SMS or data-only. Some plans are data-only.
  • Emergency calls: dial 999 or 112 for emergency services in the UK. Your device must have a usable mobile connection to place an emergency call.

Managing data and costs

  • Monitor data usage in your device settings so you don’t accidentally exceed a plan’s allowance.
  • Turn off background data for apps you don’t need, or restrict apps to Wi‑Fi only.
  • If you rely on tethering/hotspot, confirm your plan supports it; some plans or networks may limit tethering.

Troubleshooting

  • No signal after activation: confirm the eSIM profile is active, selected for data and data roaming is enabled. Restart the device.
  • Can’t add eSIM: check the device is updated to the latest OS version and that the device supports multiple profiles. If your phone is carrier‑locked you may need to unlock it first.
  • Data slow after allowance: check whether the plan has a fair use policy that reduces speeds after the daily allowance — some plans include a 1 Mbps fallback as noted in the plan description.

Backup options

  • Keep your original SIM in case you need to revert quickly.
  • If the eSIM doesn’t work with your device, you can buy a local physical SIM once in the UK.
  • Use Wi‑Fi for data-heavy tasks like video calls and map downloads.

Final practical tips

  • Activate the eSIM before you fly if you want to arrive connected, but don’t remove your home SIM until you’ve confirmed the eSIM is working.
  • Label plans clearly in settings so you don’t confuse which line is set for data or calls.
  • If you need a UK phone number for two-factor authentication or verification, check whether the plan includes voice/SMS.

Roam Star plans available

The Roam Star catalogue includes the plans listed above — choose the plan that matches your travel dates and daily or total data needs, and read the plan description for any speed‑throttle or fair use notes.