Welcome to my Leona guide and thanks for taking a gander! Leona is quite an amazing tank, but she, like many other champions, has her share of problems. She is fairly strong against squishies early game, but her damage is nothing to be feared late game.

Pros:
- Two stuns (and a snare, technically)
- Eclipse makes her even tankier
- Fun to play, radiating light everywhere
- Passive works to help your team do additional damage

Cons:
- Not the best farmer early game
- Damage drops off mid to late game
- Not very intimidating
- Not as much health as desired for a tank
- Not the best AP ratios

As you can see, I have one more con than pro, but don't let this discourage you! Leona is a great champion, and hopefully in the near future she will get a slight buff in either AP scaling or base damage.

The Masteries that I chose were pretty much basic tank masteries.

I put a point in Greed because it's an extra 1 gold per 10 sec, bringing up my Gold/10s (with Philo Stone) to 20 gold per 10 seconds. I actually think that the Utility Mastery might do better, but the only buff you will try to get as Leona will be Baron, though you may occasionally steal a buff or two from an enemy when they die to you.

The points in Good Hands is because that extra 5/6 seconds that you spend dead could really change the outcome of the game.

Armor and Magic resistance are always good to have on a tank, as well as some dodge and the dodge proc to go along with it. HP5 based on Mana is great, too.

Recommended:
Exhaust: Exhaust can change the outcome of a 1v1, 2v2, or even a full on 5v5 team fight. It can severely prevent an enemy member from doing anything for a few seconds while your team can destroy them.

Flash: Always a good summoner spell to have handy. You never know when you'll be out of position and pulled in by a Blitz pull or accidentally use Zenith Blade into an enemy champion while farming. Or it can just get you out of a team fight when your health is extremely low.

Ghost: Ghost is a good summoner spell, usually as a replacement to Flash. It can help you run from the enemy team or get back into lane/the team fight.

Fortify: Fortify can be useful when you are unable to defend a turret or when an enemy turret dives for a first blood or an easy kill. Its additional nine damage while off cooldown can be useful too, but you usually won't have the damage output for such a thing anyways.

Viable Choices:
Clairvoyance: Clairvoyance is usually a summoner spell for support champions, but I guess Leona could use it. It always helps keying in on where your opponents are and making sure they aren't coming to get you when you're over extended pushing an undefended turret.

Teleport: Teleport is also useful, but not one of the best choices. It can be used to escape when you don't have much time to run, too. But mainly getting from the location you're in to a team fight would be the most ideal use for it.

Cleanse: Cleanse can be useful in a team fight to continue stunning or a 1v1 battle to get away easier.

Ignite: Ignite can be good in combination with auto attacks to get first blood, or preventing a person from healing during a team fight.

Unneeded:
Heal: Heal isn't really that needed of a summoner spell. Yeah, it can possibly prevent first blood or save a team mate, but a tank really isn't the one who should be getting heal over a support champion.

Clarity: As long as you manage your mana (you shouldn't really need to use your abilities all that much in the beginning of the game), you shouldn't need Clarity.

Rally: Just a given "no". It's not worth it...

Revive: Once again, you shouldn't want to get Revive over other summoner spells.

Smite: ...

Sunlight

Leona's passive, Sunlight, makes her a very good duo-laner. It also is very effective in team fights, so make sure you don't spam your skills all at once. A good way to utilize this is to use your Zenith Blade to at least charge several enemies with Sunlight, following up with your Shield of Daybreak to stun the AD carry or a glass cannon on their team. Then, when your Eclipse detonates, all of the surrounding enemies will be charged with Sunlight as well.

Shield of Daybreak

Leona's Q, Shield of Daybreak, charges up her next auto attack to deal additional magic damage (allowing you to do bonus damage to turrets!) and stunning the target. During the laning phase, you can use Zenith Blade to charge into a target and auto-attacking the champion you land on to stun them while your lane partner (if they have any damage) can severely injure them.

Eclipse

Leona's W, Eclipse, shields Leona for three seconds adding armor and magic resist, then detonates after the duration. If any enemies are hit by the blast, the duration of the shield is extended by an additional three seconds. This can be useful when you charge at a target with Zenith Blade so that after you land, your Eclipse will deal a nice burst of damage, lowering their health.
There is currently a possible bug with Eclipse in which it can proc Banshee's Veil prematurely. If you're standing next to an enemy with Banshee's Veil and they're in the radius of detonation and you turn your Eclipse on, it will actually remove the spell shield provided by Banshee's Veil without anything really happening.

Zenith Blade

Leona's E, Zenith Blade, creates a solar image of Leona's sword in a line in front of her dealing damage to all that it passes through, then "teleports" Leona to the last champion that the Zenith Blade hit, if there was any champion hit. This temporarily immobilizes the last champion it hits for a half of a second, so if you can land it while chasing an enemy, your team can most likely catch them.

Solar Flare

Leona's ultimate, Solar Flare, is an AoE stun/slow skill shot with a very large range. Anyone hit by it takes damage. Those hit in the center are stunned and those on the outside are insanely slowed. You want to use this near the early middle to end of a team fight or to initiate on their glass cannon or AD carry. If using it once a team fight has broken out, use Solar Flare on any grouped up enemies as that will prevent them from doing much, if not anything. If there are no groups of enemies, target the glass cannon or AD carry.

The order that you get your skills isn't really that important. Honestly, your Eclipse is probably the skill you need the most, though. The skill order that I gave makes it so you level your skills equally, prioritizing the skills that are handiest at level 1-3.

I get Zenith Blade first in most situations because it's very useful to bush check and without a way to get to your opponent, there would be no reason to get Shield of Daybreak with laning. Now, if you are going to go after the enemy's jungle buffs such as blue or red, you're going to want to grab your Shield of Daybreak first because that's a very valuable stun to get.

For your second skill, if you're getting laned aggressively and you have tons of enemy minions coming towards you, this is where I advise that you get Eclipse next as it has a lovely AoE burst and can help kill those minions. If you're equal in lane, get your Shield of Daybreak to try and get some stuns off for possible harassment.

For level three, you'll just get the last skill you haven't gotten because all three of Leona's skills are extremely useful. If you really feel like you need either more AoE damage or armor/magic resist, then max out Eclipse first. If you're able to get a lot of harassment on their turret(s), prioritize your Q. Otherwise, your E can be used for farming minions once your team starts roaming amongst the map some more.

Core Build:
Philosopher's Stone: This is a very useful item for health and mana regeneration. It as well can be built into either a Shurelya's Battlesong (which gives health, CDR, and a team movement boost) or a Eleisa's Miracle (which can be an alternative for the Tenacity present on Merc Treads).

Sunfire Aegis: This item is what will help you farm late game. Combining this with a Zenith Blade and Eclipse combo, you should be able to take out minion waves easily.

Banshee's Veil: An essential tank item that blocks an enemy ability every 45 seconds. All ways a good idea to get this item. Early game, it can help with laning since it restores health and mana upon leveling.

Recommended Items:
Mercury's Treads: A great set of boots for tanks because of the Tenacity. However, if you need more armor, you can get Ninja Tabi (for armor and dodge, helps with the Nimbleness mastery) or Boots of Swiftness if the team has close to no crowd control or magic damage.

Shurelya's Battlesong: A good item to build your Philosopher's Stone into should you get Mercury's Treads as it gives health, CDR, and a movement speed boost to all nearby allies for a few seconds.

Situational Items:
Thornmail: Against a team with a lot of just "right click" attack (AD) champions, this is a definite must.

Force of Nature: Really good in most situations as it adds movement speed and health regeneration. The magic resist is usually helpful since most champions deal magic damage in one way or another.

Warmog's Armor: If you're struggling with the constant output of damage and aren't comfortable with only around 3000 health and over 200 armor/magic resist, this is a good item to get to increase your health by over 1400.

During the laning phase, it is possible for Leona to solo, but it is not recommended! Her passive Sunlight is useful when you have a partner! You're not going to be able to farm too well due to being a melee champion, so last hits may be hard to get when you're with a ranged champion or a full on farmer like Nasus. You want to be with an ally that can deal nice damage while you have an enemy stun locked for a couple seconds. Partners such as Anivia, Caitlyn, Ashe, Akali, or other high burst/carries can really help with getting kills during the lane process.

If during the laning phase you are with another support champion such as Taric or Soraka, you won't have very much damage output, thus you'll have limited harass. Just play it safe, and have the champion in mid come to your lane for a gank every now and then.

For team fights, make sure you have all of the champions that can do damage with you before you initiate. Once everyone's ready, and you're preferably in your turret range or no turret's range, initiate with your Zenith Blade on the squishy glass cannon or AD carry. Once you shoot your Zenith Blade, I recommend you activate your Eclipse right then so it can start counting down for the detonation. Shield of Daybreak their AD carry if they're still alive or use it to whoever is focusing down your AD carry. If a glass cannon or AD carry is still giving your team problems, use Solar Flare on them, or if they clump up.