One of the largest concerns I've had with my plans to travel for a year is whether or not I will be able to reliably stay connected to work and things that I need to be able to monitor.

As part of my job as a Software Engineer, I am on call when systems or sites experience an incident, and need to be able to be paged reliably at any time of day. This has been easy so far, I just put my phone number in PagerDuty, configured it to call and text me, and installed their app. This means I get a minimum of three alerts any time one of our systems detects a problem. Easy when you have one phone number, but what about when your SIM card is being changed out every month?

Another problem to consider for iPhone users is iMessage. Most people use iMessage through their phone number and Apple ID email address. This gets tricky when you replace your SIM card though, because your old phone number gets removed from your Apple ID and iMessage, and there is nothing you can do about it. When friends try to send messages to that old number, they never get through as a result.

So what can we do about this?

Devices at my Disposal

Right now, I have an iPhone X and an iPhone 7, both of which are carrier unlocked personal phones. This is important for making sure iMessage still works, more on this later.

Cell Plan

Currently my plan is through Verizon, and I'll be going to/from the US several times during the year, so I will likely keep an active Verizon plan.

In each country, I'm going to be getting a local SIM card through Remote Year that's probably data-only, and definitely won't have a consistent number I can be reached at.

I also signed up for Google Fi recently as a backup, because it's super cheap ($20/m, + $10/gb) and will be a nice backup to have around the world.

So I'm going to have a minimum of three active SIM cards on me at all times, all with valid phone numbers, but I'm only going to have one phone. The key to all of this is Line2.

Line2

Line2 is a phone provider that is basically just an app you install on all of your devices that uses data to make phone calls, and you even get a local phone number as part of the plan. As of the time of writing, their Standard plan in $8.30/m for a year.

The Setup

For those of you keeping track, I now have three active phone numbers. I installed the Line2 app on my primary phone, and then set up my Verizon and Fi numbers to forward calls to my Line2 number. This means that all three of my phone number end up dialing my Line2 app, which only requires data to work, it doesnt require an active cellular connection.

When I put the Fi SIM in my phone, I lost iMessage through my Verizon number, and realized that the same would happen with any of the local SIMs. This presented a bit of a problem, but after some reading I found out that Apple de-registers phone numbers from your Apple ID when the SIM for the number is removed, and another SIM card is put in.

This is what the spare iPhone is useful for. Just pop the Verizon SIM in there, let the number re-register to your Apple ID, and then you can turn the spare phone off and the Verizon number will stay registered to your iMessage account. Super convenient.

Admittedly, I still haven't left for the trip yet, but I've tested this pretty extensively and havent had any problems using iMessage, recieving calls from PagerDuty, or getting calls from all three numbers simultaneously. Hopefully this works for you too!