Sunlight

(Passive): Innate: Leona abilities mark enemies hit with Sunlight for 1.5 seconds. Any damage dealt by allies (other than herself) consumes Sunlight, dealing Ability power 25 − 144 (based on level) bonus magic damage.

Note : Sunlight's mark damage is credited to the allied champion and not to Leona.
The damage will benefit from allies' magic penetration and will apply any spell effects they have (including Spell vamp icon spell vamp)
Each Sunlight application does not stack and simply refreshes the debuff's timer.

(Discription:) Active: Leona next basic attack gains 50 bonus range, deals bonus magic damage and stuns her target for 1 second. Shield of Daybreak resets Leona basic attack timer.

Notes : Shield of Daybreak will cause Muramana Shock damage to trigger twice with a single basic attack.
The enhanced attack will apply other on-hit effects and can critically strike as normal.
Critical strikes do not interact with Shield of Daybreak's bonus damage.
Shield of Daybreak's bonus damage will affect towers, but not inhibitors or the Nexus.

(Discription:) Leona raises her shield, gaining Armor icon bonus armor and Magic resistance icon bonus magic resistance for 3 seconds. She then deals magic damage to all nearby enemies and retains Eclipse's bonus resistances for an additional 3 seconds if she damages an enemy.

Notes : Eclipse has no cast time and does not interrupt Leona's previous orders, unless she is in the beginning of an auto-attack, in which case the attack itself and its animation will get canceled.
Eclipse's bonus resistance do not factor in themselves.
Spell shield will block the ability but the buff's extended duration will not be prevented.

(Discription:) Active: Leona projects a solar image of her sword, dealing magic damage to all enemies struck. If she damages an enemy champion, she will dash to the last one struck and root them for 0.5 seconds.

Notes : Leona will automatically attempt to attack the target she dashes to.
Spell shield will block the damage but not the dash if being the last target hit.

(Discription:) Active: Leona calls down a beam of solar energy to the target location after a 0.625 second delay, dealing magic damage to all enemies it hits and Slow icon slowing them by 80% for 1.5 seconds. Enemies hit by the flare's center are instead Stun icon stunned for the same duration. Casting Solar Flare empowers Leona next basic attacks with Incandescence, gaining 100 bonus range and dealing bonus magic damage.

Notes : Solar Flare grants sight in a 350 radius for the duration.
Casting it to a location the enemy has no vision of bush will not show any visual effect, but enemies around the area will still be affected.
Incandescence's attacks will apply Sunlight Sunlight.
Incandescence's stacks fall off all at once, but the duration refreshes if Leona attacks an enemy.
Spell shield will block the ability's initial cast and the on-hit damage from Incandescence.

You should play the meat shield, essentially standing between the enemy adc and your adc. Then when it is time to initiate the fight stun lock the enemy adc and let him get the kill.
Rinse and repeat.
It is frowned upon if you steal the kills from your ADC, because they are the carry and carries need kills to carry.
It's ok to get kills if you know your ADC isn't gonna get the kill anymore. But don't get yourself in danger to get a kill, your ADC needs you. Don't take a kill if your ADC can kill it.
Leona excels as an aggressive support, but she is prone to dying due to her having to go all-in to do anything. Here are a few tips for Leona:
Laning Advice
As Leona, aim for bush control. Consider starting with a Stealth Ward and Relic Shield 2x Health Potion By maintaining bush control, you keep the enemy laners on their toes, worrying about when you may strike, this will make the enemy support spend wards in the bot bush to reveal you which it gives to your jungle opportunity to gank unseen and walk freely in the river.
If you are confident about being able to take the enemy's poke, walk up to them a bit to scare them off. Try not to do this unless you have all three skills though in case you get into a sticky situation (or in case you find an opening to engage!).
Engage intelligently. If you find both yourself and your carry at Level 2 while one or both of the enemies is still Level 1, strongly consider engaging; you will have the upper hand and don’t be greedy, don’t Flash or dive for a kill cause you might die without getting the kill, aim to make the enemy use his summoner spells ( Flash/ Heal). If you miss this window of opportunity, look again at Level 3 (when you have all abilities and the enemy ADC has no summoner spell left to use) and Level 6 (when you have your Solar Flare).
Don't be scared of taking kills. Ideally, your carry will get every kill. However, your W deals a deceptively high amount of damage at higher ranks, don't beat yourself up if you accidentally take one. In addition, if your carry is dead or is otherwise unable or unlikely to take the kill, don't be afraid of taking it! It's probably better for you to take the kill and have some extra gold than to let them get away.
General Advice
• Delay picking your first skill. You should typically take either Shield of Daybreak or Zenith Blade first, the other of the two second, and Eclipse third, prioritizing your Solar Flare and your Eclipse. Take Zenith Blade first if you find yourself in a Level 1 team fight where multiple enemies may be hit by your Zenith Blade otherwise, if nothing happens and you just go into lane normally, take Shield of Daybreak.
• Be willing to sacrifice yourself for your carry. Once Leona gets off her Zenith Blade and Solar Flare, she becomes significantly less useful. At this point, if the enemies have kill potential on your carry, consider leading them away from your carry to have your self killed instead. However, be careful about this: do not sacrifice yourself if your carry will surely die, nor should you sacrifice yourself if your carry is likely to live.
• Do not use Zenith Blade in every time. Sometimes it's better to stay in the back line.
• Do not be afraid to use Solar Flare. Leona's Solar Flare has a relatively short cool down. You don't always need to use it aggressively; you can use it as zone control to stop or delay enemies from chasing you.
• Try to stun-lock. If you happen to catch onto their carry with your Zenith Blade, follow up immediately with a Shield of Daybreak to stun, then centre Solar Flare on the carry. This will lock them up for almost 3 seconds, which is plenty of time for your team to blow them up.
• Be familiar with your passive. Leona's passive, Sunlight, allows her team to do additional magic damage onto the tagged targets. This can be useful for taking . Since Sunlight does not stack, try to not blow all your abilities at once if it can be avoided, especially against and . Instead, apply a stack of Sunlight onto the target, wait for a team mate to proc it, and then apply another. This really helps with burning down the high HP.
if enemies are approaching, leave your skills unused in case they attempt to engage a fight.
• Know whether you need to initiate or peel.
o If your team comp has nobody to start fights, you may be expected to initiate. In this case, consider building Randuin's Omen. Position yourself in the front line, and when the time is right, either use your Solar Flare or your Zenith Blade to initiate. When you Zenith Blade into the enemy team, use Randuin's Omen to decrease their damage output.
o Alternatively, if your team already has initiation, you should be a peeler. In this case, build more support-oriented items like Locket of the Iron Solari which is a mystic item and fits thematically as well and stay near your carries. If any threats approach, dissuade them with your Shield of Daybreak and your Solar Flare.
Above all else, practice! With time, you'll notice yourself getting better and better.

Activating Randuin's Omen will just slow down the enemy and does not mitigate damage. the active and the passive don't quite perfectly align. Arguably, though, if you can manage to get the enemies to auto you which they probably will if you dash into them, their damage output on autos will be lowered slightly .
In lane, you primarily have two jobs:
Jump on the enemy and stun them until they die. The key is that you must do this only when your team is actually likely to win the resulting engagement. Making that sort of judgement can be extremely difficult and is mostly a result of experience, but in general you're looking for some combination of these factors:
o They have low health, you don't.
o Their cool downs particularly escapes and summoner spells are down and your team's are not.
o One of them is isolated; your AD could be in range much sooner than their partner, giving you a 2v1 for a short amount of time.
o Their jungler is not near
o Your jungler is near
• Threaten to do the above. Even if they're playing too cautiously for you to have a chance to actually go in, you still exert a sort of pressure, so try to be as threatening as possible (without actually putting yourself in undue danger). This means control the bushes, try to keep them away from your minions and so on. If they can't farm because they're afraid of you, you still win the lane without a single kill.
As for taking kills, your ultimate goal is to get your carries more kills, and so you should back off if the enemy is clearly going to die. However, if you think they might get away, or they might otherwise kill one of your team before they go down, then definitely you should risk taking the kill yourself- remember, assist gold is 70% of the killer's award. People who talk about 'kills stealing' are generally just being childish.
Note that this does not mean you should actively be trying to take the kill for yourself rather than have another team member get it- rather that it's okay that occasionally you'll accidentally get the kill because you were both attacking the enemy and your hit happened to be the last.

Some Tips for Playing Leona Support Like a Pro

when you play properly, you can be one of the more powerful support champions in League of Legends. Her passive enables her to have a powerful amount of damage when utilized properly, and her kit has access to a ton of crowd control. Here are five tips that will improve your Leona play.

5. Use your Solar Flare Aggressively and Defensively.

Solar Flare is a great tool for picking off over-extended target picks on multiple targets. Use this ability to engage crucial time fights and set up picks with your team.
On the flip side, don't be afraid to stand near your sole carry champion and wait for any enemy assassins acting foolish.

4. 0 or 100 No In between

It's important to realize that one of Leona's biggest weaknesses is that she struggles to disengage once she has committed to one of her Zenith Blade jumps. Her lack of mobility means that she will be unable to protect her self or the AD Carry if for some reason a potential threat unexpectedly shows up.

To combat the issue, before engaging, always try to have an understanding of where the enemy jungle is located.
If you believe they are on bottom side, try to at least make sure your jungle is in position for a counter gank and you have proper ward coverage.
Also make sure you don't allow your enemies on the lanes themselves to walk past you and burst your allied laner.
Try tanking a few major enemy abilities while having your Eclipse active so that you can reduce those abilities effectiveness.
Also check if your ADC has healing spell ready cause this might help you to receive some heal during the fight, and save a relic shield passive to receive heal when you kill a minion during the fight this will give you a little heal and to your ADC.

3. Auto Shield of Daybreak Auto

It's actually possible to reset your auto attack animation on your first auto attack with Shield of Daybreak.
There is a few ways you can utilize this combo.
• Use this combo to clear wards that are placed right at your feet, If you are quick enough you can clear the ward without a sweeper.
• If you are looking for a way to gain a small boost of damage per second in isolated fights, execute the combo.
• Use this combo to push turrets faster.

2. Pace Your Abilities When Fighting Early Game

passive, Sunlight, allows Leona to gain additional damage when consumed by allied champions.
When paced properly with an allied AD carry, bursting down enemy champions early game becomes very easy enabling you to push early leads.
As the game progresses this becomes slightly less relevant as Leona's damage becomes not as potent, but can also sometimes be the difference between an enemy walking out with 50 health and zero.

1. Guarantee your Abilities(Combo).

Landing one crowd control ability means that you should land another one.
If you land your Solar Flare, follow up with your Eclipse then Zenith Blade into your Shield of Daybreak .
If you walk up and auto attack with your Shield of Daybreak follow up with your Eclipse then Solar Flare then Zenith Blade if the enemy flash or activate a movement speed item to run away.
If you land a Zenith Blade, follow up with you Shield of Daybreak and an Eclipse then follow into your Solar Flare.
That aside, if your ADC gets hooked you want to pretty much blow your combo on their ADC. Not - once he lands his pull and knock'up he's down to autos before 6. Generally you want to position in such a way that the enemy lane knows you're going to retaliate in the event of a hook.