But these missiles have only been tested with relatively light satellites, so it's unlikely they would reach this far with the heavy payload of a warhead.
Only one of these tests has failed under the current leader, signalling their operational readiness.
There is also some contention over whether North Korea has miniaturised a nuclear weapon so it can attach it to these longer-range missiles.
The regime claims it has already mastered this technology; experts say if North Korea doesn't already have the capability, it's a year or less away.
But disturbingly, submarine-based launches are much harder to anticipate than a land-based launch.
North Korea's intermediate-range ballistic missiles have a maximum range of 4,500 kilometres.
The missile in this category with the longest range is the ER Scud. That puts all of South Korea within range, as well as Osaka, Japan's second-largest city.