Openline pairs cleanly with a O2 UK primary line. Your O2 UK SIM (physical or eSIM) keeps handling your personal calls, SMS, and 2FA; Openline handles cellular data at travel prices.

How to set it up

  1. Install Openline as a second eSIM. Do not remove your O2 UK line.
  2. Once both lines are visible, set Cellular Data to Openline for the country you're travelling in.
  3. Keep Default Voice Line on your O2 UK line so calls to your regular number still reach you.
  4. Turn Data Roaming off on the O2 UK line so it never accidentally picks up expensive roaming.
  5. Turn Data Roaming on on the Openline line — that's required for travel eSIMs by design (Openline isn't charged as roaming to you).

Notes for O2 UK customers

  • Wi-Fi calling on your O2 UK line keeps working while Openline runs — a helpful failsafe when a hotel Wi-Fi is decent but a partner cell isn't.
  • If you have O2 UK's built-in international roaming plan, disable it before your trip or you'll double-pay: Openline will handle data, and your O2 UK plan will still bill you for it if left on.
  • O2 UK may occasionally push a "Welcome abroad" SMS. Ignore it — it's informational, not a bill unless you actually use their roaming.

Still stuck?

Reach Openline support 24/7 through any of these channels:

When you write in, include your purchase code (the OL-… code we emailed you) and, if the eSIM is already installed, its ICCID (Settings → Cellular → tap the Openline line). That's enough for us to find your plan and diagnose without back-and-forth.