[pinjiz]

In Germany, only Deutsche Telekom (and resellers such as Congstar) supports IPv6 on mobile (for both prepaid and postpaid). And it works great, even when tethering.

Since you're from the UK, I suppose you are a Vodafone customer and therefore roaming in the Vodafone network in Germany (which does not support IPv6 yet).

On some networks/devices you might have to enable IPv6 explicitly, by setting the APN to IPv4/IPv6.

In Singapore, Singtel seems to be the only provider that supports IPv6. Unfortunately only for postpaid plans.

[geocar]

I was using Three last time I was in Germany. I just switched to Vodafone because they offer 4G tethering when roaming internationally.