does the google nexus 7 (2013) work in japan?

Would I be able to access wifi or do I need a sim card? My tablet is the 16 gb version.

wifi is an international standard so will work anywhere, provided you have access to it. Free wifi is uncommon in japan and places that offer it usually need registration. You also have to option of getting a data only sim.

Thanks! I'm aware that free-wifi is uncommon in Japan, and that certain places require registration.

So just to clarify, I don't need a sim card then? The reason I ask is because my tablet does not have a slot for one.

Obviously you can't use a sim if your tablet doesn't have a slot for one. But if you would like to use your tablet anywhere, you might look into renting a mifi device.

You can rent pocket wifi that works with any tablet or computer with wifi capabilities. I am using one from Japan Wireless with my Nexus 7 right now. I ordered it before leaving the states and had it delivered to my sister in laws house in Sasebo. It was waiting for me and includes a post paid return envelope.