The Skinny on SIMs

Read on to learn what SIM solution I picked in the countries below and why, but for a comprehensive database of prepaid SIM information, look no further than the Prepaid Data Sim Wiki. This is my go-to source of information for SIMs in every country. They've covered the carriers and plans in extensive details. Consider my information below a simplified version for a handful of countries. 

Australia 🇦🇺

Though a number of carriers offer competitive prepaid SIM options in Australia, I went with Vodofone AU because they would ship the SIM card (free) to an Australian address before I arrived. In my case, this was an Airbnb, but most hotels will hold mail for you as well if you let them know something is on its way. 

Vodafone was offering (and seems to always be offering...) a 50% off promotion of their (AUD) "$30 Combo Plus Starter Pack".  AUD $15 got me 25 GBs of data, as well as unlimited local calls and texts valid for 30 days. This is one of the most generous SIM deals I've come across. 

Coverage along the Great Ocean Road was solid as well as some of the rural areas of Tasmania. 

You are meant to be able to register and activate your Vodofone AU SIM online by providing passport details, but I wasn't successful in my several attempts. Luckily it I wasn't too faraway from a Vodofone kiosk that could complete the setup for me by scanning my ID. 

Bulgaria 🇧🇬

There are a lot of good deals be found in Bulgaria as far as prepaid SIM cards. During my visit I went with M-Tel principally because they had an outlet down the street from my hotel. A SIM with 3 GB of data and 100 minutes of local calling valid for 14 days cost be less than $4. M-Tel has since been rebranded as A1. Coverage in Sofia and Plovdiv was trouble-free, although it did occasionally cut out in the countryside on the way to the famous Rila Monastery. 

European Union 🇪🇺

The EU's Roam Like Home rules mean that (within reasonable limits) a SIM card from one EU country (e.g. Ireland) will function in another EU country (e.g. Spain) just as it would at home (i.e. as it would back in Ireland). 

In order to get public transit directions or request a ride share from the airport, it's helpful to have a SIM ready to go and working the moment you step off the plane. The trouble is, most prepaid SIM cards have an expiration date that will often mean it's dead by the next time you visit the EU. Many carriers also have rules that make it nearly impossible to add credit to a SIM card to "keep it alive" from abroad. 

A great option is Vodafone UK, which allows you to top up a SIM card online using PayPal. (Paying directly with a credit card can only be done with a UK card). This SIM card will expire after 12 months of inactivity. I've used this SIM in Italy, Malta, Ireland, and Portugal with no difficulties by adding a £10 "Big Value Bundle" (250 minutes, unlimited text, and 3-8 GB data depending on current promotions). It's not only convenient to skip visiting a shop and setting up a new SIM in each country, but I've found Vodafone's prices are competitive compared to the local options in the aforementioned countries. Elsewhere in the EU it's so cheap to setup a local SIM that the extra hassle might just be worth it. In Bulgaria, for instance, I setup a SIM with data/voice/text for $4. 

BREXIT: This may all change as a result of the UK's withdrawal from the EU. During the transition period, however, the Roam Like Home regime remains in place. 

Ireland 🇮🇪

If you're visiting the Republic of Ireland, your startup costs will be higher than if you purchase a SIM in Northern Ireland (or elsewhere in the UK). I've got family on both sides of the border, so I chose to buy my SIM in Belfast. Vodafone UK offers prepaid SIMs at better prices that the carriers in the Republic of Ireland and they work seamlessly down south. See the UK section below for more information. If you're sticking to the Republic, get more information here. 

Thailand 🇹🇭

There are many, many options to get quickly setup with a prepaid SIM in Bangkok's Suvarnabumi airport or in the city. Because my flight from Hong Kong was arriving past midnight, by which time I expected many of the airport shops to be closed, I purchased the  "Happy Tourist Sim" from carrier dtac. The SIM can be ordered and paid for online (removing the worry of finding a currency exchange counter open at 1 am) and picked up from a desk at the airport, 24/7. For about CAD $10, I got a SIM valid for 8-days with 15 GB of data. 

United Kingdom 🇬🇧

Vodafone UK is one of the few carriers I've found that offer a prepaid SIM card that can be kept alive indefinitely by adding value online. The SIM will expire after one year without activity. You can add value online with several carriers, but the advantage of Vodafone is that you can do so using PayPal. Most UK carriers will only accept top-up payments with a UK-based credit card. 

Visit a Vodafone-branded store in Britain or Northern Ireland and buy a SIM for £0.99. You can then add the service bundle of your choice. I went with the £10 "Big Value Bundle" (250 minutes, unlimited text, and 3-8 GB data, depending on current promotions). 

The EU's Roam Like Home rules mean that (within reasonable limits) a SIM card from one EU country (e.g. Ireland) will function in another EU country (e.g. Spain) just as it would at home (i.e. as it would back in Ireland). This SIM card will expire after 12 months unless credit is added. I've had this SIM for three years and have used it in Italy, Malta, Ireland, and Portugal with no difficulties.

BREXIT: This may all change as a result of the UK's withdrawal from the EU. During the transition period, however, the Roam Like Home regime remains in place. 

United States 🇺🇸

Options for affordable prepaid service in the US are surprisingly limited. As a Canadian, I make frequent trips across the border and for years I've wondered why there isn't more competition in the visitor-SIM market. I've used a number of Canada-based solutions meant for roaming in the USA, such as Roam Mobility. I've also used AT&T's $3/day talk + data plan. None were especially reliable, easy, or inexpensive.

This year I came across US Mobile. You can have a SIM card mailed to any US address free of charge (or internationally, for a fee). SIM starter packs normally cost USD $3.99, but click the promotional link on the landing site for a rebate which reduces the cost to $0.29. 

US Mobile offers bespoke plans that allow you to pay for just what you need. This past winter I did a road trip through Southern California. I had the SIM mailed to my hotel in LA. Setup online using the hotel's WiFi was quick and simple. I chose a plan with 75 minutes talk and 1.5 GB of data for USD $14 after tax. Plans are valid for 30 days.  

US mobile also offers seemingly competitive international data packages for use outside of the USA, though I haven't yet tried this for myself. 

Vietnam 🇻🇳

Setting up a SIM card in Vietnam means attending an office of the network provider in person for your passport to be photocopied. Also note that Viettel stores accept cash only. (Vietnam is very much a cash-based economy). 

For about VND 200,000 (CAD $13), I was set up with a local number, 200 minutes of calling and 5 GB of data valid for 30 days. The staff at the Viettel store in Old Hanoi had a laminated card printed in English outlining the details of each tourist SIM plan. The price was somewhat more than what's listed on the Data SIM Wiki. Whether this is due to changes in price over time, or inflation for tourists, I can't be sure. Service was strong all over the country, including the Con Dao islands.