Against leona, Make sure you hit level 2 at the same time or before Leona as her level 2 all-in is very strong. In the bottom lane, this is the first minion wave followed by 3 melee minions. 

Leona’s roaming potential is much stronger than most Supports. If she is unable to kill the enemy in lane, she will look to roam. As soon as she leaves lane, make sure you ping your team and communicate that she is missing.

With good wave management, you can make it very hard for Leona to engage. By keeping the wave closer to your side of the map, you will make it impossible for her to engage with her e without diving your Turret. Against leona, Make sure to hit Level 2 at the same time or before Leona that its level 2 all-in is very strong. In the lower lane, it is the first minion wave followed by 3 melee minions. Leona is the much stronger roaming potential than most Supports. If she is unable to kill the enemy in the track, she will seek to wander. As soon as she leaves the track, make sure to ping your team and communicate that it is missing. With good wave management, you can make it very difficult for Leona to engage. By keeping the wave closer to your side of the map, you will make it impossible for her to engage with her without diving your Turret.