[Closed] Running iPhone as sat nav - how to/which SIM?

hotspot it to your current phone?

I'm sure you can download maps over WiFi at home and then use it SIM free.
Not sure on the apps but it's definitely possible.

Use Google maps. Download offline maps of anywhere you might think of driving, over wifi, at home before you start.

No sim required.

Offline maps need updating every three months.

I do this with an old iPhone 5s which only gets used for maps and downloaded music on Spotify for the car.

as lunge says you don't need data. just download the Google Maps app, download a map of your region over wifi at home and away you go.

Downloaded 'offline' maps used to need re-downloading every 30days or so but i'm sure Google changed this recently such that they last a year...

I use a 3 sim. On their 321 PAYG tariff its 1p per MB. Just put a tenner on it and it'll last you for months. No need to top up, the credit will never expire as long as you use the phone at least once in 180 days. Easy to try, get a free sim, if it doesn't work out it hasn't cost you much

Car or biking?

You can use maps offline (you need to download them first).

https://www.techadvisor.co.uk/how-to/mobile-phone/download-google-maps-offline-navigate-3629702/

For biking, I've never tried it without a SIM, but I use Viewranger and I reckon it would work with no data as long as you download the maps. Full UK OS maps are £25/year, or you can buy map tiles as you go.

Best SIM-only deals I've seen is Smarty if you decide you need data.

https://smarty.co.uk/

Three do a free Sim that gives you 250mb a month for nothing. If nothing else it's worth it for trying out to see if you get a decent signal where you ride. Aa long as you start the ride at home on your wifi the data required will be negligible if you need to reroute and it has to come up with a different course.

Thanks guys, it for the (motor)bike - I have offline maps but still need the data for occasional use, searches, traffic etc.

The 1p MB from Three looks the cheapest but not considered the idea of hotspotting to my main phone...

If it’s for the car or road biking then there are many apps that allow you to download offline maps and do routing.

I’ve been using Here Maps for a while now. It’s free and you can download whole countries for use offline. The points of interest are also stored offline so you can still search for places without data. If you have a data connection it will also have traffic information and plan a route to avoid the traffic.

GPS in and of itself does not use data.

Things that do require data: assisted GPS to speed up an initial satellite lock; loading of non-cached / non-local maps; traffic updates.

For your usage case I'd just tether it to my existing phone, assuming there was some sort of compelling reason why I couldn't take it to CEX to flog and use my main phone as the sat nav instead.

Install CoPilot or Here, or TomTom, although TomTom requires a subscription to get the best out of it. Waze is free as well. With all of those the mapping data is installed with the app, and you can chose what regions you install. There are cheap SIM-only deals now offering huge amounts of data though, I heard one advertisement on a car radio earlier today, didn’t recognise the network, but it was £10 with 30Gb of data/month, IIRC.
However, even with all that data, I would still go for one of the apps with pre-installed maps - before I started using Satnav for work I used either Google or Apple Maps, and there were places I was on holiday where there was zero network available so impossible to download a new set of map data. Having data available does mean you can get live traffic updates with some apps, TomTom in particular is very good for that, I used it for my job as a Logistics driver for British Car Auctions, I reckon I drove roughly 100,000 miles with its help, but that’s rather more than average!