Hello! I will be visiting the UK in December and will be driving. My iPhone network is Sprint, so I don't really want to switch to an international plan since it's quite expensive. I downloaded an app named Navmii for the UK. Is anyone familiar with it? Or, is there a relatively inexpensive GPS that I could purchase on Amazon or rent there? Thanks!
When driving, I usually prefer a dedicated navigation system. You can usually find one which includes or accepts international maps for around $100, especially if you belong to a membership warehouse or order off the internet.
As far as the iPhone goes, you should be able to add (or replace the Sprint SIM depending on the model with) a UK pay-as-you-go (PAYG) pre-paid SIM for around £30. I used an O2 SIM which had plenty of data and call/text allotment. Just remember to remove the PAYG SIM on return or you phone won't reconnect to you Sprint network. I also take a paperclip (to eject the SIM drawer) and small plastic case, such as a SD memory card case, to safely store my 'home' SIM when traveling abroad.
I researched on Amazon purchasing a Garmin or Tom Tom. You can buy them with the UK maps downloaded.
We took our own Garmin. We bought a UK SD card from Amazon ($35.00) and it worked perfectly for our two, month-long trips to England, Scotland and Wales. It was nice having the familiar gps unit with us.
The car(s) we rented had built-in navigational units. We didn't "order" the gps when we reserved our rentals prior to our trips (we saw no need to pay $11.00 a day for something we were already planning on bringing with us!). Bith times, the rental places said we could just go ahead and use their gps unit, no charge. But, not trusting their word, we never even turned it on!
Gps units are nice. But, old-fashioned paper maps are sure wonderful, too!
We bought a Garmin Nuvi from either Amazon or Walmart online (whichever had the better price), bought UK maps from Amazon, and have used them (very gratefully) on trips to the UK. If you do buy a GPS, practice driving with it in the US and familiarize yourself with its settings and features before your trip to the UK.
On our last two trips to the UK, our rental cars unexpectedly came with free GPS but we found our Garmin easier to use. We also found that typing in postal codes (e.g., WD25 7LR for Warner Brother Studios London or OX20 1PP for Blenheim Palace) rather than addresses worked best for finding places with our GPS.
Have a wonderful trip!