The first time you fight tamers is part of a questline starting from Orgrimmar/Stormwind. The Pet Battle trainer will send you to tamers across the continent. After you beat them, he'll send you to Outland, Northrend, Cata Zones and then Pandaria. You can only fight them once you've reached their stage of the quest chain. Once you've beaten their quest, you unlocked a daily rematch for each of them.
Battle pets fastest leveling? No idea. I used a damn messy tactic to get there. I might aswell share it.
Pick level 1 pet, battle level 2 pets until your pet levels/you find a rare (or an uncommon) pet. Catch said pet, put it in place of those who still are level 1.
Move on, battle level 3 pets, catch uncommons and rare and replace level 2 pets.
Rinse and repeat...
I did this all the way to level 20, then i kept three pets to raise to level 25. I don't know if this is the fastest way, but certainly it's one of the funniest.
Get 2 level 25 flying pets and the pet you want to level up, go to any pool in VotFW, get your low level pet out, then switch for one of your flying pets and kill the aquatic ones realy easy. With the 50% extra exp hat, im leveling a pet from 1-25 in no time like this.
I get the sense that people greatly underestimate the amount of exp you get from three L25 wild pets. Sure, the trainers are great, but they're not *that* many wild battles' worth of exp. Especially when you consider that being epic/legendary, the trainer battles take some time even if you've got a good team and strat for each. You can chew through wild pets, because you still get the same amount of exp for beating a poor quality pet as you do for a rare. Mowing down three poor pets is much, much faster than a trainer battle.
Wild pets are also far less likely to kill your powerlevel pet than a trainer pet.
What I do when a pet is starting at level 1. I put on my 10% xp cap and head to Dragonblight. From there I fight the birds near Wyrmrest Temple with a team of Level 1/25/25. Let the level 1 do one round ability then swap out (so he gets XP). After about 3 fights it should be roughly 8-10. Once it hits 10 then I head to Outlands and start from Hellfire Pennisula and do every trainer in Outlands including Grand Master. Usually by the time I hit the Grand Master they have dinged 25.
Originally Posted by Bilbo Baggins
However I think I am missing something, because when I go to a tamer there isn't an option to battle them.
You can only battle a trainer once. Once you unlocked the dailies (by defeating the Grand Master in that region) you will then unlock the dailies which allows you to fight the trainers once per day.
1.) Do one pet battle in Valley of the Four Winds so that the level 1 pet doesn't get oneshotted during the trainer battle.
2.) Do the Valley of the Four Winds trainer daily with an Onyxian Whelpling. The whelpling can solo all three pets, you can switch your level 4 pets in and out during the burrow phase of the second pet.
3.) Head over to the Kun Lai pet trainer, do his daily.
4.) Since I am that lazy, I repeat those two trainers on a daily basis until my pets get to 25...may not be the fastest but the fastest regarding playtime.
As others have said, take your lowbie with 2 level 25s. I prefer a cat as one and do most of my leveling in the middle zone that has halfhill. Beast vs critter is very good, has a damage reducer and a health gain kill ability. The 3rd pet I use is Wild Crimson Whelping, in case I don't feel like flying all the way down, I just do the Vale aquatic pets. This is also how I farm lesser charms.
I like to batlle near the bmah. There are only critters and with the exp hat, you can get your lv1 pet up to7-8 in one battle. With Kunlai runt, they melt quite fast.
Only problem is, it gets quite boring after a while.
Similarly the Anubisath Idol is great for these. His Sandstorm reduces the damge of some pets, specifically the Vale and Kun Lai trainers, to pretty much zero. That said the first pet of the Vale trainer very rarely kills a level 1, usually you can survive it and with food and the hat hit level 12 from that battle. Then 19 I think it is from the Kun Lai one, then it slows down but is still pretty trivial. I always have issues with the Townlong trainer though so I skip that one now.
Additionally the vale pets near the water, are pretty much guranteed non-fatal to level 1s. Think its the skimmers but they'll either heal, do a really weak attack or pump so can't 1 shot a level 1, if you can't wait for the next round of dailies.