If you're a frequent traveler, you're forced into a choice overseas. You can either keep your U.S. number and receive your regular calls and texts, or go for a local SIM card and get lower rates, at the cost of people from home not being able to contact you.

There are a bunch of ways around this—Skype numbers, WhatsApp, KnowRoaming stickers and such—but globally, the most popular, least-employed-by-Americans strategy is to use a dual-SIM phone. These phones can connect to two networks simultaneously, juggling two numbers, making calls and texts on both, and picking the best network for data.

Dual-SIM phones aren't just for travelers, either; many people abroad use them to keep a personal number and a business number on the same device, or to balance promotions and deals on different prepaid networks in the same country. Strategy Analytics said in a report earlier this year that more than 500 million dual-SIM phones will be sold worldwide in 2016.

In general, though, dual-SIM phones are few and far between in the U.S. An OpenSignal report from early 2015 said we have the world's lowest percentage of dual-SIM phone usage, at just 2 percent.

That's because our carriers have forbidden dual-SIM devices from entering their lineups, and phone makers don't generally build U.S.-compatible devices that don't at least have a chance of being sold by carriers. New manufacturers have tried to make a splash with dual-SIM phones in the U.S. (we profiled some in 2012), but they've generally run up against the shoals of carrier disapproval.

In other countries, there are dual-SIM versions of many popular phones, including the Samsung Galaxy S6 and the LG G4. But while you can gray-market import dual-SIM phones, most of those devices won't work on U.S. LTE networks, and even if they do, you probably won't have a U.S.-applicable warranty. In general, if you want a phone that works well on our LTE networks, you need a device designed for the country.

We've found nearly half a dozen good dual-SIM phones for sale in the U.S. that you might want to make your primary phone. They're all compatible with AT&T and T-Mobile. (Nobody makes a dual-SIM phone compatible with Sprint or Verizon). Of the smartphones, three run Android and one runs Windows Phone. Apple has never made a dual-SIM device, and has shown no interest in doing so—perhaps because U.S. carriers are such a large market for iPhones. And one of these devices is a feature phone—a $20 feature phone.

If you need two numbers, pop your SIMs into one of the five phones below. For more, see The Best Unlocked Phones and our Cell Phone Product Guide.