re using my cell phone in Germany to call home to Colorado

Dial "+1" and then the regional code (e. g. Colorado) and the number.
This is interntional ITU standard and works in all networks and countries.
You can test it also while you are still at home.

"+" by long press on the button which displays the plus sign.
"1" is the international code for USA and Canada.

As long if you have still your SIM in your phone people can reach you by dialing your number the same way they always dial.

EDIT: Inform yourself about costs for incoming roaming calls - some old tariffs let you pay a minute fee for receiving calls.

You don't have to do anything if your numbers are correctly stored in your online contacts (such as Google contacts). Store them in the format +1 (or choose the US flag) then the number.

eg + 1 202 456 1414

Your children would do the same to call you.

If you use the Verizon International service all you have to do is press the number in your "Contacts" list. no need to do any added dialing or make any changes. And people trying to reach you don't have to do anything either. And that's anywhere in the EU or GB.

The dedicated international help desk is (or was) 1-800-711-8300. Verify that your phones are set up for international use, and if you need to update the roaming capabilities. The people at the international desk are very knowledgeable pleasant, and helpful. They can also email you detailed dialing instructions for calling back to the U.S. On our last trip we had all of the numbers we might possibly need in our contact list. If we needed to make a call we simply highlighted the number, hit "Send" and the phone did the rest even without the "+ 1" in front of the U. S. number. If someone in the U.S. needed us, all they had to do was call as they always would. That might have changed, so do check with Verizon to be certain.

I always get the Verizon international plan and have used it has recently as this past June in Switzerland.

Make sure you have roaming turned on under cellular options under settings.

The phone numbers do NOT need a +1 in front of them. All my contacts are just area code and phone number. When I make a call from Europe, I do the same thing as I do at home in the US. Just click on the number from my contact list. Verizon does the rest and connects the call. The same works if my mom calls me from the US. She just clicks on my number from her contact list.

Verizon makes things super easy. It is well worth the cost to have data when traveling.

I don't know which plan you have, but if it's one where calls are discounted rather than free, you can always call home (and vice versa) using WhatsApp or FaceTime audio (if you have an iPhone). Just call when you have wifi (like in your hotel room), and it's completely free. If you use WhatsApp, your family would need to have the WhatsApp app, but it's easy to use.

I've done this on trips where I wanted to talk to friends and family. Then just save the regular calls for emergencies.

I found that Iif I picked the person I wanted in my RECENT calls (iPhone) the smartphone would figure out what to dial.

Another vote for WhatsApp. Easy to use video/audio calls and uses data instead of call time which is more forgiving with most international plans. Create a family travel group for your kids for texting and photo sharing too.

Use Whatsapp. So easy to use.

Whatsapp costs you zons of money - not the call itself. But based on your contents shared on that platform you will get higher priced offers on the Internet; except you use silent mode for shopping. That way Whatsapp is the most expensive communication you ever had.

You can also use Facetime. Use if over wifi and you burn zero minutes of your calling plan. You can also set-up a couple of specifc call times during your trip to check-in.

I long ago gave up on trying to contact my friends in the US by phone when I'm in Europe. Because of the 8 hour time difference, it seemed that whenever I wanted to call, they were either sleeping, or had just gotten up and were too busy getting ready to go to work to talk. When they came home in the evening, I was already asleep.

I take my small netbook to Europe with me, and, in the last 10 years, every place I have stayed at has had Wifi. I just send an email whenever it's convenient for me, and they answer by email whenever it's convenient for them.

Works like a charm!

I’m guessing the parents would want to be reachable to their children back home at any time. I would not rely solely on Wi-Fi.

And some of us would like to be easily reachable by their elderly parents. And that doesn't mean by Whatsapp, Facetime, or even them calling the "confusing" French number you just gave them.

Another calling/ texting app that is supposed to ACTUALLY be private is Signal. Many of our members in the Thin Blue Line use it because it's private and encrypted.

Of course, the people you want to call should also have Signal.

We subscribe to T Mobile's international plan, and if we receive or make a "normal" call, we pay 25 cents per minute. Sometimes restaurants or hotels have What's App contact, so we call them over wifi, we're not charged. But when they're NOT using What's App, we'll make the "normal" call. Because the calls are short, our bill isn't ghastly at the end of the month.

Folks back home calling your regular cell number don't do anything different than when you're home and you don't do anything different to call them.

As a responder above indicated, to start the "normal" call to another country you'll need first to use the plus sign (+) followed by the country code (start hanging around a country and the country code becomes obvious or so an internet search)... the press the number.

With that said, sometimes the number I want to call isn't so obvious. And I don't do it correctly. So then I resort to asking a local for help...

BTW, to get a plus sign, press zero longer that is necessary and the phone will do the work.