You land in another country, switch off airplane mode and everything seems normal. Messages come through, maps load and you get on with your trip. Then your next bill shows charges you didn't expect.

That gap is usually data roaming. Here's what it is, how it works and the simple settings that keep you in control before your next trip.

What Is data roaming?

Data roaming is when your smartphone uses a mobile network that doesn't belong to your provider. Inside your provider's coverage area, you connect to its network. Outside it, your phone connects to a partner network instead, based on an agreement between your provider and that operator.

Roaming usually starts automatically. Unless you've changed a setting, your phone connects and starts using data as soon as it finds a usable signal, which is why it's worth understanding before you travel.

How does data roaming work?

Your phone carries an identity tied to your account, stored on your SIM card or eSIM. When you arrive somewhere your provider doesn't operate, your phone looks for a partner network. That network confirms you're an active subscriber with your home provider and grants access.

From there, your data, calls and texts travel over the local operator's network and the usage is recorded on your account. The handoff takes seconds. You may see a roaming icon or a different network name on your screen, but your phone won't stop to ask whether you want to continue.

International vs domestic roaming

• International roaming happens when you're abroad and connected to a foreign network. Costs depend on your destination and what your plan includes.
• Domestic roaming happens inside the U.S. when you pass through an area your provider doesn't cover directly and your phone connects to a partner network. It's less common, but it's still technically roaming.

Data roaming vs mobile data

These two settings sit close together on your phone, but they control different things:

• Mobile data controls whether your phone can use cellular data at all. Turn it off and your phone only uses WiFi.
• Data roaming controls whether your phone can use cellular data on a network that isn't your provider's.

If your plan doesn't cover roaming, most travelers want mobile data on and data roaming off. That setup works normally at home and stops cellular data use abroad.

What happens if data roaming is turned on?

With data roaming on and no international coverage in place, your phone behaves just like it does at home. That includes activity you may not notice:

• Background app refresh, including email sync and app updates
• Automatic photo and file backups
• Location services and maps
• Streaming video, one of the heaviest ways to use data

If data roaming is off, your phone can still connect to WiFi. Depending on your plan, calls and texts may still work over the local network and may be billed separately from data.

Why roaming charges add up

At home, most plans bill a flat monthly rate. Abroad, if your plan doesn't include international coverage, pay-per-use data is billed by the megabyte at rates set by destination. Loading maps, sending photos and letting apps sync in the background can use more data than you'd expect, and per-megabyte charges add up quickly.

That's why many providers offer flat daily passes. A set daily rate makes your costs predictable, which helps if you plan to use your phone throughout your trip.

Should data roaming be on or off?

For most travelers, the answer is off by default and on when you're covered.

• Turn it off if you haven't checked your plan's international coverage or you plan to rely on WiFi.
• Turn it on if your plan includes international roaming or you've added a daily pass for your trip.

How to turn off data roaming

On most phones, open Settings, then look for Cellular, Mobile Network or Connections depending on your device. Find Data Roaming or Roaming and switch it off. Menu names vary by manufacturer and software version, so you can also search your settings for “roaming.”

If you're a Spectrum Mobile® customer, you can also manage your International Roaming settings in your Spectrum account or the My Spectrum App before you leave.

How to avoid roaming charges

A few steps before and during your trip cover almost every situation:

1. Check your plan before you travel. Know whether international roaming is included, available as a daily pass or billed per use at your destination.
2. Add a daily pass if your plan needs one. A flat rate keeps costs predictable if you'll use data during your trip.
3. Keep data roaming off until you need it. You can turn it on briefly to check directions, then switch it back off.
4. Connect to WiFi when you can. Hotels, cafes and airports often offer WiFi, and many messaging apps work over WiFi for calls and texts home.
5. Turn off background app refresh. This keeps apps from syncing while you're not using them.
6. Download before you go. Offline maps, playlists and shows saved at home won't use roaming data.
7. Use airplane mode for full control. With airplane mode on and WiFi switched back on, your phone won't connect to cellular networks at all.

Spectrum Mobile international options

Spectrum Mobile offers several ways to stay connected abroad, depending on your plan.

Unlimited Plus and Unlimited Plus Premium

Both plans include unlimited talk, text and data in 215+ countries and destinations. Data speeds are reduced after 10 GB on Unlimited Plus and after 20 GB on Unlimited Plus Premium. Learn more about what's included with Unlimited Plus Premium.

Global Day Pass

Available on Unlimited plans, Global Day Pass includes unlimited talk, text and data, with reduced data speeds after 1 GB. It's $10 per line for every 24 hours in 215+ countries and destinations and $5 per line for every 24 hours in Canada and Mexico. Additional premium data is available in 1 GB increments with Global Pass Extra.

Global Pay-Per-Use

Available on all Spectrum Mobile plans, Global Pay-Per-Use charges only for the calls you make and the data you use, at set rates by country.

Plan ahead before you travel

Data roaming only becomes a surprise when it runs without a plan behind it. Before your trip, check what your plan covers, set your roaming preferences and decide how you'll stay connected. You can compare Spectrum Mobile international service plans and search rates by destination anytime.