any unisex Onsen in Tokyo or outside?

Hi I'm living about an hour outside Tokyo with my gf and want to find any unisex onsens in the Kanto and Ibaraki regions

Takaragawa in Gunma-ken is a really famous onsen. It is all rotenburo (outdoor baths) and is unisex. It is known for having the largest outdoor bath in Japan and is regularly featured in travel brochures and shows. There is also a ryokan there.

Travel there is not that easy though. You can take the train to Minakami and then a bus to the Ryokan. Or drive. It'd be about 1.5-2 hrs from Tokyo to Minakami and another 45min-1hr to the Onsen.

I highly recommend it and it is absolutely beautiful in the show or during autumn.

Many onsen ryokan and hotel also have a family bath (Kashiki Furo?) which is a smaller bath that you can "borrow" for a set period of time, e.g. 30 minutes. This is so that a whole family can bath together. There are places with both inside and outside family bath. This may be preferable to a communal bath -- unless you're going for the view ;)

The Izu peninsula isn't far out from Tokyo. If you go to Atami (nice little resort town reminiscent of Milan) you can change to a train line that goes right down the peninsula along the East coast. I don't remember the line name or station name but it was the 2nd last stop. There's an onsen just a little walk from the station that is RIGHT by the sea. Girls and guys together (though the girls were outnumbered when I went). It was great, 'cos when I got too hot I just went down and jumped in the sea. The waves were a bit big but the water is crystal clear and the boulders are big and smooth with no oysters or sharp bits. If you're a decent swimmer and can keep your eyes open under water you can catch a wave and land right on a boulder. I felt like a seal! Not sure it's technically allowed, but felt awesome to go between these environments - turbulent, cold skinnydipping to a relaxing steaming hot onsen not 10 metres apart.