To quote Chico Marx on the topic: “Why a duck?”
I went down the Wikipedia list of islands in Norway and found a slightly better “tunnel-only” one: Ringvassøya, 663 km2.
All larger islands in Norway have bridge access of some kind. The slightly larger island of Kvaløya is a weird case which I think doesn’t count. It has no bridge directly to the mainland, and it does have a tunnel direectly to the mainland. But it is also connected by bridge to another island (Tromsøya) which has a bridge to the mainland. So if the rule is “it is possible to drive there but you have to go through a tunnel to do so” then Kvaløya is out.
While we’re at it, WTF Dakota? You need a north one and a south one?
Yes, that’s what I intended. Thanks for the work. Ringvassøya is likely the tunnel winner.
I’ll note the Scandinavians seem to do tunnels a lot, so they’re good at them. For example, in the Faroes, there’s a roundabout under the sea. Think about that. To have a roundabout, you need to have two roads intersecting, so that means two tunnels intersecting. Not your everyday type tunnel:
Do only bridges directly from the mainland count? What about taking 2 bridges as with the island of [Kvaløya] (Kvaløya (Tromsø) - Wikipedia)? You can drive to it from the mainland over bridges, There’s a lot of rules in this contest.
No. Somewhere upthread I said island hopping via two or more bridges counts as getting there by bridge. If the island hopping is via tunnels, then that’s a tunnel answer.
I didn’t think there’s a lot. But reality is messy, so there always a need for rules to handle exceptional cases. It doesn’t matter what the question is.