If you are planning to use your mobile when you travel, here are five easy ways to guarantee a consistent experience when you’re gone, and when you get home, stop nasty bill surprises.

1. Ensure That Your Phone Will Work

First, make sure that your phone is working in the destinations you expect. Cell companies around the world use various technology and frequencies and there is no guarantee that any of them will work on your handset. Older Verizon phones, and particularly Sprint phones, can be troublesome.

First, check the user manual on your computer. This will operate in most of the world whether it is sold as a “world handset” or supports quad-band GSM. If you purchased your phone from your cellular provider and are not sure if it would operate overseas, please contact customer service.

The most recent smartphones in many parts of the world will support calls, text, and at least 4G data.

2. Check for International Roaming Packages

This can be a very expensive practice to use your devices in overseas. When traveling internationally, many cell plans do not include any calls , texts or data, and casual usage rates can be extremely high. It’s not uncommon to hear people returning from a holiday of one or two weeks and getting a bill of thousands of dollars for cellphone use.

Check to see if your cell company has any products ready for foreign use, to prevent this happening to you. Although many such packages are still costly compared to using your home phone, they are generally much cheaper than prices for “pay as you go.”

3. Find Out If It’s Unlocked

You can do that with an unlocked GSM mobile, if you want to skip roaming charges altogether. You can delete the SIM card from your current cell company with one of these, and replace it with one from a local company in your destination.

Depending on where you’re going in the world, the card itself will cost a few bucks, while credit worth $20 will usually give you enough calls , messages, and data to last for at least a few weeks.

Unfortunately, it might not be unlocked if you failed to pay the full price for your cell. There are exceptions, however, and purchasing an encrypted phone or getting it encrypted after purchase is becoming easier than it used to be in the United States.

4. Turn Off Cell Data (and Use Wi-Fi Instead)

There are several ways to stop paying a lot if your mobile isn’t unlocked and you don’t have a decent international roaming package.

The most logical thing is to turn off cellular data to your destination before you board the plane and leave it until you get home. You could have spent hundreds of dollars downloading e-mail at rates of up to $20 per megabyte before you even got to the luggage carousel.

Instead, just use Wi-Fi while you’re gone. Most hotels now offer wireless access, free or at reasonably low cost, and when you’re on the go, cafes and restaurants will fill up the gaps.

5. Use Google Voice or Skype Instead of Making Calls

Finally, whether you use Wi-Fi or cellular data, consider using mobile applications such as Skype , WhatsApp or Google Voice when you need to keep in contact with family and friends back home. Rather than charging high international calling and text rates, these apps let you speak and send messages to everyone around the world for free or cheap as long as you have decent internet access.

Using Google Voice lets you, for a small charge, call and text most U.S. and Canadian numbers at no cost, and any country outside it. Skype also has low per-minute calls and text rates, and both apps allow you to call other service users for free wherever they may be.

WhatsApp lets you text and/or call any other user of the app at no charge, as does iMessage, Facebook Messenger, and several other services. With a little preparation, heading overseas with your smartphone doesn’t have to be a difficult or expensive proposition. Have fun!