porting my number to Google Voice was the best decision I ever made. When I get to a new country I just buy a new local SIM and access my long term phone # through GV over data. Can get a bit weird with call forwarding, which I think is only allowed for US numbers, but it's not too big a deal. Can receive SMS and place calls just fine.

Will you be traveling within one region or multiple, e.g. Americas, Europe, Asia, etc.? I'm not sure about Europe but in North America, between US/Mexico/Canada, I didn't need to purchase separate SIMs because Verizon gave me service in all three countries. Traveling in Asia now, I just find it easier to purchase local SIMs and have a local number. The problem you run into with not having a local number, especially if you're staying for months at a time, is that local people and business cannot contact you. When it comes to lodging, metro cards, bike shares, reservations, etc., a local number just makes things smoother. For contact with family back home, I use message apps or an Internet phone service like Google Voice. There are phones with dual (triple?) SIM slots, so that could be another way to go.

If you would like to get a little technical, Twilio is the solution I’ve used for years now.

I have several numbers with Twilio in different regions; they’re all configured to forward to whichever number/device I happen to be using.

It depends on your residence right now. American phone numbers can get Google Voice which I've heard is a great service. I'm from the UK and have a 3 sim, and can use data for no extra cost abroad in most countries, including both Poland and Slovakia. I highly recommend 3! You need a UK bank account to be eligible for the abroad data, but my Irish friend did a hack where he signed up with Revolut and got access to UK bank details there. 3 also offers free calls to UK numbers.

If you have a phone that is compatible with an e-sim you can also use those. I know iPhone XR and above can use e-sims, and lots of Android phones too. Airolo is a GREAT service for e-sims - you can get them for a week for a really good price. It's immediate as well. Normally I just purchase the sim on the airport wifi and it's up and working in 30 seconds.

I've used a mix of my 3 sim and Airolo (for countries like Egypt and Canada where 3 doesn't work) and have also dipped my toes into international sims. I don't recommend international sims at all - they're expensive and unreliable from my experience. I'd rather just buy a sim at the airport than get an international one.

We are 10+ year users of google voice because it can be used free over wifi, or mobile data. USA number needed to verify initial setup of USA google account.

It really all depends on which provider you are with and their offerings / your package.

For example, I'm with 3 (UK number), I can use my phone and internet anywhere in Europe or even the USA for free! so I won't need an additional SIM card.

That said, I did buy a SIM card for when I was in Australia and I still have it incase I go back again.

I spent a month in Poland this summer and it truly is an undiscovered gem. Probably my favorite country next to Italy, and I’ve been most everywhere in Europe.

Surprisingly Poland has an abundance of wi-fi everywhere. Even in the small cities and towns, pretty damn fast reliable wifi was pretty much standard everywhere.

Just got back from two months in Italy… Not quite sure what’s going on there but definitely not the same story in that country.

i am also heading to poland in a couple weeks, maybe we’ll cross paths. I found this https://www.reddit.com/r/poland/comments/wbh2j/cześć_polacy_i_need_sim_card_with_internet_to/ but it’s old. i’m going to ask in the poland channel on the slack when the day gets closer.

ranking in polish … but you get the idea: