WIFI or just GPS in rental car for ring road tour?

Use your phone.

We always get the wifi unit, but have never paid anywhere near that much for it. Often times we get it included, but even if not, it is only around $10-$15 per day. Hotels do have wifi, but some can be very weak when you are more remote. We get it for those instances, and for when we are out hiking. We also use our regular cell with the international plan, but like to have the wifi unit for these other instances.

$1000 sounds mind boggling. A wifi unit receives the same signals as a cellphone. As long as the cellphone sim card is registered on the same network, same signal. One could buy a $100 used phone and a $15 local sim card, activate the cellphone hotspot, and save $885.

We just used Google Maps on our phones and displayed on the car’s console. Worked great around the whole country. We never had problems accessing the network.

I wouldn't pay an extra $1,000 for in-car Wi-Fi. For most Ring Road trips, that's hard to justify. Offline maps on your phone (Google Maps or Maps.me) work very well in Iceland, and GPS navigation doesn't require a constant internet connection once the maps are downloaded. The main reason to have internet in the car is for real-time weather, road conditions, and last-minute changes, but a local SIM card or eSIM is usually much cheaper than renting a Wi-Fi hotspot from the car company. I'd save the money and either use offline maps or get a local data plan instead.

Blue was going to charge me $15 a day for the wifi router, which was around $100, so I decided to just get an eSIM that would complement my T-Mobile international phone plan. Someone on Reddit did that and it worked well, so I'm using Bcengi, which is a PAYG eSIM. However, I'm sure Airalo or others would be fine as well.

What car rental company are you looking at that charges that much?

I wouldn't pay $1000 for it, but you can order from Trawire and get a wi-fi box for about $10/day. I would recommend having one because sometimes you'll need to pay for parking on the go. You can always wait to pay when you get back to the hotel, but I wouldn't risk forgetting because the extra fees are insane. I would just get one from Trawire if the difference is $1000.

There is good cell coverage in much of the country, so no. I wouldn't pay for that. Signage is good and it's ultimately a single road. You're either going clockwise or counter-clockwise. Kinda hard to mess it up.

Just back from 2 weeks in Iceland. We drove all around the island. I used an Airalo esim for my iPhone 15pro. bought 10GB, used 1/2 of that. Brought a cable to connect to the USB to USB-C in the car and my phone and plugged it in each morning with directions for the day. also used my Itunes library for music. When in the hotel at night, I used their wi-fi to download photos to Facebook, and to call my kids on Facetime.