The Moonkin is a creature whose presence brings tranquility.
- Immune to Polymorph effects.
- While in this form, you can only cast Balance spells, Remove Curse, Abolish Poison, Mark of the Wild, and Gift of the Wild
- When in Moonkin Form you are flagged as a humanoid and are immune to beast-type magic, like a Druid's Hibernate, or Hunter abilities designed to affect beasts, but you are also immune to polymorph. (It used to be possible to knock a Moonkin out into normal form with Hallowed Wands, but this has been fixed.)
- Moonkin is one of only two shapeshift forms in which a druid can deal weapon damage. (The other is Tree of Life form.) In feral forms, damage dealt is feral, not weapon damage.
- You cannot ride certain mounts while in Moonkin Form. You will also need to remove Moonkin Form in order to use a flight path; unlike the other forms, talking to a Flight Master NPC will not force the Druid out of Moonkin Form.*There are a few places where change of appearance can allow you to ride mounts in Moonkin Form, such as places were you get the fel orc costume, or vehicles in Ulduar. Shifting into Moonkin Form will not change your appearance, just give you the bonuses to Armor and Crit,and it is possible to mount. Leaving such an area will not dismount you but you will gain your moonkin appearance, making you a mounted moonkin. This same trick can be done in Wetlands with the Cursed Sailors.
- When in Moonkin Form the druid dances exactly like when using the Gordok Ogre Suit and the Carved Ogre Idol.
- It is possible to tank many instances in Moonkin form. However, the talent builds and gear required differ from a DPS role. 
- Players have given the moonkin form many nicknames. These are normally short and end with -kin; some of them are: Boomkin, a moonkin druid with a high damage output; Oomkin, a moonkin with poor mana regen; Doomkin, a good PVP moonkin (rarely used); Noob/newbkin, a bad/inexperienced moonkin druid; and Panzerkin, a tanking moonkin. Sometimes these nicknames are used to describe a particular druid, but most of the time players use them as a general term. Many moonkin druids find some of these nicknames insulting.
Tips and tactics
Invest in as many talents that increase the DPS of your spells, both those that reduce casting time (Starlight Wrath) and increase damage (Moonfury). If you are going for a group PvE build, don't invest in talents that require physical contact (like Brambles). However, if you are going for a solo PvE build, then do invest in these talents, and make sure to have Barkskin active, as you will need it if you're taking damage, even with the 370% armor increase.
Moonkin tanks ("Panzerkins") can be a strong alternative to non-tank specs through decent damage mitigation and high DPS (versus main tank specs). Moonkin tanking is rare for many reasons, but Moonkin have successfully tanked Karazhan, Gruul's Lair and most 5-man heroics. Gearing is problematic; PvE rewards do not generally support Moonkin tanking, but the Arena Rewards for druids provide some of the balance necessary. Keep in mind that moonkin armor is equivalent to plate, but will still be lower than most warriors, feral druids, and paladins because of the lack of armor-increasing talents (e.g. Toughness). Lithanial's guide to Moonkin Tankingand Thunja's guide to WOTLK Panzerkin Tanking are currently the largest sets of information about Moonkin tanking.
Moonkin have three primary abilities that are key to surviving in PvE - Cyclone, Entangling Roots, and Barkskin. Cyclone is obtained at level 70 and allows the druid to temporarily encase a target in a cyclone which makes the target incapacitated and immune to all forms of attack (lasts 6 seconds). Entangling Roots snares a target in place for up to 27 seconds, however external damage to the snared target can remove the effect. Both of these abilities give the Moonkin CC abilities which are essential for those "whoops, I pulled one too many" moments.
Barkskin reduces all damage taken by 20% and prevents pushback on your spells for 12 seconds. Obviously Barkskin is useful for mitigating damage but it also allows the druid to shift back to caster form and cast some HoTs. Lifebloom and Rejuvenation, along with the bonus healing from Lunar Guidance, increases a Moonkin's survivability considerably. Now one might ask, "both those HoTs are instant so why should I wait until I cast Barkskin to shift out and use them?" The answer to that is simple, when you shift out, you lose the 370% bonus to your armor, so you take significantly more damage, Barkskin helps to reduce that loss of armor.
Cyclone has diminishing returns in PvE and is therefore not an effective way of CC'ing a particular mob for an extended period of time. After three casts of Cyclone on a particular mob, the mob is immune to the spell.
In Wrath of the Lich King, Balance druids have learned a new powerful spell known as Starfall, which is capable of AOE damage to enemies in a very wide area dealing high damage.
A second new ability called Typhoon shoots a wave of nature power in a forward-facing cone, knocking back any enemies it hits and damaging them which has usefulness in both PVE and PVP. This has lead to the dismay of some players, as now that players have knockbacks, it is possible to take falling damage in PVP combat and take dura hits, as well as being able to push them into areas that may be difficult to find their way out of.
Moonkins do have some issues in PvP. The most noticeable disadvantage is their survivability. While they can push out heavy damage if left alone, once they are focused on they quickly become less of a threat. They also lack some important parts of utility. They don't have any way of silencing an enemy caster and if they are silenced them selves while casting a nature based spell, such as Wrath, Nourish, regrowth etc, all their healing is completely cut out for the duration of the effect making them very vulnerable. This have led many to practice "Fake casting", in an attempt to make the enemy waste their silencing ability. This is simply done by casting and quickly cancelling the cast. An attempt to work around the lacking survivability is stacking stamina. Having a 30k+ health pool can help a great deal to stay alive longer. This of course differs depending on what kind of PvP one plays. Some combos in the Arenas make stacking stamina very effective, while others work better if one stacks spell power. It simply comes down to how one plays.
With the release of cataclysm, worgen balance druids have been dubbed as "howlkin"
Starfall can be a very useful tool in PvP, because the moonkin doesnt have to channel the spell and it will auto hit any enemy player who treads to close to the moonkin. Typhoon can also be a very useful spell if a melee class such as a rogue gets up close to the moonkin they can knock the enemy player and away and change to cat form to get out of range and continue the attack.
Insect Swarm does decent damage per point of mana and its marginal reduction in hit chance isn't too shabby. Entangling Roots, unfortunately, is becoming less useful as time passes because more and more classes are being given ways to escape snare effects. If anything, it still delays a player from reaching you, which usually will give you the time to cast a Starfire/Moonfire combo. Use Starfire from range and Wrath in melee.
Most players will suggest beginning fights in Cat Form. If you are a Night Elf (and patient), simply shadowmeld and wait for your target to come in range then surprise them. Starting from Cat Form has its advantages though. If you are a competent "stance dancer" (you should be if you wish to be a Moonkin) you can Pounce and then Rip your target, then switch to Bear Form before they recover from the stun. From Bear Form, melee your target once (possibly twice if you are unlucky) to get enough rage to Bash your target. This gives you enough time to switch to Caster Form and place a Rejuvenation on yourself and switch back into Moonkin. Once back into Moonkin Form, Moonfire your target. At this point the stun should be wearing off. The rest is up to you.
- Patch 3.2.2 (2009-09-22): This form now also reduces the damage the druid takes while stunned by 15%.
- Patch 3.1.0 (14-Apr-2009): Mana cost reduced.
- Patch 3.0.8 (2009-01-20): Abolish Poison can now be used in Moonkin form.
- / Patch 3.0.2 (14-Oct-2008): No longer increases your attack power or causes you to regenerate mana off melee attacks, but now has a chance to cause you to instantly regenerate 2% of your total mana every time you critically hit with a spell.
- Patch 2.0.10 (2007-03-06): The armor bonus from "Moonkin Form" has been increased from 360% to 400% (to match Dire Bear Form).
- Patch 1.8.0 (10-Oct-2005): Significant talent changes. Added Moonkin Form.
1. Thunja 07/24/2009 Thunja's guide to WOTLK Panzerkin Tanking Retrieved on 2009-08-08.