Any way to do 3-way switch without wiring?

There are many virtual three-way options discussed in the forums. :sunglasses:Essentially you just use a battery operated device for the auxiliary switch. Eaton Cooper makes a zwave one That looks exactly like their regular mains powered switches.

Lutron pico switches will work as an auxiliary for Lutron Caseta masters and have a 10 year battery. (But if you want to use them with something other than the Lutron Caseta master, everything gets much more complicated.)

Ecolink makes a battery operated zwave switch in both a rocker and toggle style.

Or you can use any battery operated device that can talk to the smartthings hub. Then the battery operated device sends a message to the hub and hub sends a message to the master switch.

See the following FAQ (this is a clickable link). Some of the entries are battery powered, some are mains powered, some are for the US and some are for the UK, so read the descriptions carefully to make sure you’re looking at one that will meet your needs.