How to access wifi on an android phone that comes without it? I purchased a cheap smart watch (this one). It doesn't support wifi. At the moment I can surf and watch videos by being connected via bluetooth to my tablet. 

But I plan to root the device and install google play on it. I would like to install other apps on it afterwards too. It has a simcard slot and I can use a 2G network to do that. 

But I am wondering if I could either buy a plug and play module or build something that would enable me to access wifi on the watch? Or is it not possible?
I'm sorry you actually need a WiFi receiver to be able to access WiFi. If there's no hardware in it supporting WiFi, you cannot add that by means of software.