UPDATE 2017-10-15: The information in this post is outdated, see this post for an updated version.

There has been much talk about IPv6 potentially causing problems for subscribers roaming between mobile networks. There’s an entire RFC dedicated to the possible failure cases, and it has even been claimed that «until every carrier has activated IPv6 there is no way to activate IPv6 for international roaming».

My own personal experience with IPv6 roaming hasn’t been quite that bleak, so I’ve therefore decided to thoroughly test IPv6 roaming whenever I have the chance and chronicle the results here, one post per country I visit.

As I am currently attending Internetdagarna 2016 in Stockholm, I now have the opportunity to perform this testing for Sweden.

There are four mobile network operators in Sweden. However, the only one I could roam in while using my Telenor Norway SIM card appeared to be Telenor Sweden. (No big surprise, there.) Thus I was only able to test the Telenor Sweden PLMN.

The tests were performed by separately attempting to establish single-stack IPV6 and dual-stack IPV4V6 data bearers and then visiting ds.test-ipv6.com. This procedure was repeated for all available access technologies I was able to use. The results were as follows:

Visited PLMN MCCMNC Tech IPV6 bearer IPV4V6 bearer
Telenor Sweden 24024 2G 10/10 (IPv6-only) 10/10 (dual stack)
Telenor Sweden 24008 3G 10/10 (IPv6-only) 10/10 (dual stack)
Telenor Sweden 24008 4G 10/10 (IPv6-only) 10/10 (dual stack)

Thus I can conclude that IPv6 roaming in the Telenor Sweden PLMN works 100% perfectly. Kudos to Telenor Norway and Telenor Sweden for making that happen!