Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
I'm a bronze Udyr main with over 110k mastery points in Udyr along with Mastery 7 on him with summoner name Raexys. This is my first guide so I'll try to explain why I put what where and I'm completely open to criticism from everyone.
So, this is a build designed to be tanky and still put out the damage and sticky-ness Udyr can exhibit. First off, since we're keeping the blue theme here, Stalker's Blade is a must for us because of the color and that it is an awesome item for Udyr because of the speed it provides to allow us to either a) chase our target, or b) run from groups. Cinderhulk is a good option here because of the Bami's Cinder passive it provides which is synergistic with the auto-attack based damage Udyr does, second off, it provides extra tankiness for us which is always good. I chose Mercury's Treads because they are blue as well as the resistance from hard cc that they give which is the main threat to Udyr in games, if you get stunned and focused you become dead, this is also a good option because your bear stance, blue smite, and quints provide enough speed in my opinion for the functionality of Mercury's Treads. Next up is Trinity Force. This is literally one of the best items on Udyr because of raw stats it gives especially with the added attack speed buff. The Spellblade passive on it provides amazing burst for Udyr especially with the Tiger Stance active and the fact that Udyr is an auto-attack based champion, we take full advantage of this passive with our fast stance changes. Next up is Frozen Mallet, this item provides raw Health Points and Attack Damage which work well with our build for the tankiness and since we are an Attack Damage damage build. The passive is the main reason for this item because it helps give the stickiness we need to avoid being kited. Next is titanic hydra which is awesome with this build for the cleave effect for jungle clear along with the tankiness and overall dps spike it gives us. Lastly, we have Guardian's Angel which is an awesome in this build for the passive which is literally a lifesaver late game as well as the very good resistances this item provides to help out or hp tankiness we have.
We of course took smite because this is a jungle build. I chose ghost over flash because of the lower cool down which makes almost 2 uses of ghost per flash along with the buffs it got in the recent patch. This is also good for Udyr so you can escape or dive into a team with bear stance active since you don't need the immediate escape in most situations because of your tankiness and outrun capability.
MS quints are a must for Udyr for avoiding being kited. Flat armor seals are awesome for the first clear finishing with enough hp to get Tiamat and your hunter's potion. Scaling cool down reduction glyphs provide that little extra boost to cool down reduction we need with Trinity Force to be able to spam our stances which scales really good with Udyr. Attack Speed marks provide for an easier first clear as well as some early dps potential before you get Titanic Hydra and Trinity Force.
Unyielding because it scales better late game. Explorer for easier chasing. Runic Armor for better turtle stance and jungle healing. Insight for more ghosting and smites. Swiftness for the tenacity which Udyr needs lots of so he isn't kited. Strength of Ages for the end-game scaling it provides as well as the fact 2 of our items scale off of max hp which this helps some with. Fury because more auto attacks = more damage. Expose Weakness because we aren't the primary damage dealer on a team, we tank, stun, and peel; we do damage, but not the main source. Vampirism for the sustain in jungle and better than flat ad and ap in my opinion. Oppressor because one of our main abilities is a stun.
Just your typical Udyr tiger max order. Take tiger level 3 instead of bear unless you see an immediate gank you're near or you know you'll get invaded.
I start gromp, then proceed in order to blue, wolves, raptors, krugs, red, scuttle if possible, wolves, gromp, scuttle. (You can invade or gank after the red if you so wish, I like to finish clear personally for the earlier tiamat and item advancement)
This is a late-game focused build but has some serious power spikes after you finish tiamat, bami's, and trinity force. So the #1 rule is don't fight if you don't have a good chance of winning. AKA don't fight losing fights. You are Udyr, you have amazing clear times especially after you finish tiamat and bami's. A plus side to this build is since it's farm-heavy, you will l almost always come out about 1 or 2 levels ahead of your team. Play somewhat passive until after you get trinity force, after that look for available ganks and picks. Before that. only gank if it is almost a guaranteed kill. For ganks, run in with ghost if they are in the middle of the lane or save it for the chase. Either start with tiger before the gank for the active then switch to bear or if it is a mobile laner start with bear and possibly ghost.
The most important things to remember are: you are a off-damage tank, when your power spikes are (tiamat, bami's, trinity force, and titanic), and farm it out to win (you are udyr so your jungling after tiamat is top tier), and give me constructive criticism :)