Experience with FP1 in New Zealand

I am on holiday in New Zealand and was looking forward to use my German fairphone overseas.
I chose a prepaid SIM card from the national carrier Telecom New Zealand, who currently uses the name Spark. They are supposed to offer the best coverage.
Nevertheless I experienced no connection at all as soon as I left denser populated areas.
After some research I discovered that the Spark mobile network is completely build on 3G technology. Old services like voice and SMS are provided via 3G data protocol.
Obviously the 3G data module inside the FP1 is not of the best quality. As soon as I am outside of reach in terms of data connection I loose all other services as well.
The second mobile network in New Zealand is operated by Vodafone. They still employ the old technology parallel to 3G technology.
I bought another SIM card of the alternative mobile service provider 2degrees, who beside its own fully equipped but yet low coverage network makes use of Vodafone’s network. In SIM slot 1 this works beautifully.
I swapped the Spark SIM card to slot 2 and of course, it did not work in slot 2 at all, because slot 2 is restricted to 2G only.

So my recommendation for FP1 users visiting New Zealand is definitely to use 2degrees or Vodafone for SIM slot 1 and perhaps additionally add a Spark SIM card, too, because Spark offers a very extensive WiFi (WLAN) hotspot network across New Zealand, which offers 2 Gbytes per day (!). So this Spark SIM card would not work as intentioned, but provide access to the Spark hot spot network.
So lots of fun for all FP1 visitors to beautiful Aoteroa aka New Zealand!

Just a quick note that you can toggle which SIM gets 3G connections via Settings > [Wireless&Networks] More… > Mobile Networks > 3G Service. (But only one SIM can have a 3G connection at the same time)
Not sure if it is still useful to you, but 3G coverage is usually less extensive than 2G coverage (less reach). Most operators have a network coverage map somewhere - e.g. for spark there’s an interactive map on their 4G page that can be toggled to show 3G coverage via the box left of the map.