Using my phone as a wifi-hotspot had enabled me to access everything I've tried so far, which includes the store, friends, chat, trophies, and online scoreboards in-game.
I've yet to try a multiplayer game through it, but will test it later.
Using: Samsung Galaxy Nexus
PS
Vita Wifi Tesco Mobile contract sim (UK)
gaming.stackexchange.com/users/19531/Ric
While I haven't got a PSVita to test, I have used a multitude of WiFi devices (PSP, computers, iPads) with my Androids WiFi-tethering without any problem.
Since the phone will present itself as a regular WiFi hotspot, the only potential problem source is your provider (that may, or may not, block certain services).
gaming.stackexchange.com/users/9271/Tzarium
This is not limited by Sony's hardware whatsoever.
When your phone tethers, it acts as a Wi Fi hotspot and you are able to access all internet functionality like any other WiFi access point.
The only limiting factor is the speed; since you're accessing via your phone's 3G connection it's likely going to be slower and more unstable than a normal WiFi connection, but that depends on your connection strength, phone hardware ect.
There is no limitation in the PS Vita hardware.
gaming.stackexchange.com/users/11920/Ben Brocka
From what I understand, the Vita does not support ad-hoc tethering , but will connect to proper WiFi hot spots, which it seems some phones support and some do not ( read more here ).
I have a Droid X through Verizon.
I do not pay the monthly fee for tethering, but I do have a few tethering apps from the Market that work great with my laptop.
My Vita cannot connect to any of them.
I would love to find out what the difference between "ad-hoc" and "hot-spot" tethering is and if my phone is capable of the latter.
gaming.stackexchange.com/users/18801/Langdon
Tethering to an Android works perfectly on a PS Vita.
I've tried using a Wifi and 3G (expired data plan)
PS Vita and used Google Nexus One, Google Nexus S and Samsung Galaxy Nexus to test.
Running the Internet Connection Test shows that you can connect to the Internet and PlayStation Network successfully.
I have a short guide here: http://www.xtremepsvita.com/2012/05/22/3g-gaming-on-a-wi-fi-only-ps-vita-using-android-iphone/
gaming.stackexchange.com/users/17865/Niraj Shah
I have an Android phone able to provide 3G data connection over WiFi Tethering, and I would like to know if the WiFi version of PS Vita is able to use it to play online and access leaderboard features or if instead is limited in some way by Sony firmware/hardware.
PS Vita Wi-fi and tethering
gaming.stackexchange.com
<ps-vita>
gaming.stackexchange.com/questions/51932
gaming.stackexchange.com/users/730/Drake
Vita does not support ad-hoc tethering but will connect to wifi hot spots. PS Vita can connect to most, if not all, smartphones that are able to be set up as a hot spot. This handheld console does not bare any limitations regarding that, by Sony.
It is mentioned that the PS Vita can indeed connect via tethering to a phone.