holiday in USA this year - what is the best thing to do with my phone

My personal experience from a trip to the USA in March (Was written in response to someone else, so some things may not apply to you personally, but 95% will) :

As someone who spent most of March in Northern California, this is what you should have done before your trip, but also, WHAT YOU SHOULD DO NOW, even if you only have a few days left of your trip :

If you have an eSIM compatible phone, download a specialist travel data only eSIM, such as HOLAFLY, which offers unlimited data as standard. So, with unlimited data, that would be “one and done” for you. (Other travel eSIMs, such as Airalo, offer various “buckets” of data, such as 5 GB, 10 GB etc. which if used up, have to be topped up with another “bucket” of data, so that’s why I suggested Holafly, with its unlimited data, to you.)

As travel eSIMs are data only, you would need to use WhatsApp for any calls and texts. 

If you don’t know much about travel eSIMs, there are plenty of videos on YouTube videos about them, I recommend searching for “Project Untethered” travel eSIMs on YouTube, but of course, ONLY when connected to WiFi 😉

Another option, and one which I used, was to download an eSIM from the American MVNO, “Tello”, which offered an American number, and therefore minutes and calls in addition to data. Tello is an MVNO on T-Mobile in the USA, in the same way that Smarty is an MVNO on Three.

If you have a look at Tello and decide it’s the way to go, feel free to send me a message, and I can give you my referral code, which gets us both $10 Tello dollars credit. I won’t openly post it in this reply to you, as I don’t want to potentially break forum rules, and in any case, as much as I would appreciate the $10 Tello Dollars, as I am keeping my Tello eSIM active ahead of emigrating to Arizona, I feel that Holafly is probably your best option, although Tello does include calls to 60 countries in their plans, which proved useful for me, as I had to make a couple of calls back to the UK during my trip, which didn’t cost any additional money, as Tello include them in all plans as standard. 

Either of the options which I have outlined will give you “cost certainty”, with no further unwanted surprises re costs.

To sum up - Using Smarty outside the UK and EU is simply too expensive, as you have now found out. You should always use a specialist travel eSIM, or a local SIM or eSIM in the country you are visiting. Sorry Smarty, I love you like jelly tots, or should that be smarties, but you are too expensive to use outside the confines of Europe !