Yuumi Runes explained
There's one set of runes for Yuumi on patch 15.12 that is the clear favorite for LoL players and pros alike. The best Yuumi rune paths on the position 
Support are 
Sorcery as the primary path and 
Resolve as the secondary path with a pick rate of 89%. Besides picking runes on Yuumi you should learn how to play Yuumi and if you are interested in pro matches take a look on how a pro builds Yuumi. If you want to discuss 
Yuumi then you should visit the champion subreddit.
Yuumi runes from primary path
Sorcery empoweres abilities of Yuumi and increases the available champion resources. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Summon Aery is the best keystone rune to run on Yuumi. This keystone rune adds more poke damage to your abilities. And additionally grants an extra shield, whenever Yuumi empowers or protects an ally with abilities. Other primary runes on Yuumi are 
Manaflow Band, 
Transcendence and 
Scorch.
This is usually followed up by taking Manaflow Band for additional mana and mana regenaration. Transcendence for some more Ability Haste. Scorch increases your control in the early game.
Yuumi runes from secondary path
When it comes to your secondary path, most Yuumi players prefer to go with Resolve. Resolve empowers the survivability of Yuumi and increases the tankiness. On the Resolve path, the best runes for Yuumi are 
Font of Life and 
Revitalize.
Font of Life provides your teammates with more sustain by healing them whenever they attack a champion whose movement you've recently impaired. Revitalize inceases heals and shields you distribute or receive.
FAQ for Yuumi Runes
Which is the best keystone rune on Yuumi?
The best keystone rune on Yuumi is Summon Aery. This Yuumi runes setup is then referred as Yuumi Summon Aery.
What runes does Yuumi use?
Runes from the paths Sorcery and Resolve are the most used runes on Yuumi. For the exact pick rates of Yuumi runes used, you have to study the rune distribution presented.