The Lakelight Lily is a beautiful blue flower with a dew-like bud and is a local specialty that can only be harvested in Fontaine. It's used as a character Ascension material for Furina and possibly other Fontainian characters in the future.
Whether you're looking to Ascend a character now or save resources for later, I recommend farming for Lakelight Lilies now as there aren't enough to fully Ascend a character in one day. Here's where you can find them.
Where to farm Lakelight Lily in Genshin Impact
Lakelight Lilies only bloom in Fontaine's Erinnyes Forest region, located in the large area surrounding the Opera Epiclese and Marcotte Station. They only grow close to sources of water, so you'll find most Lakelight Lilies clustered in the Loch Urania and Weeping Willow of the Lake. They're easy to spot and pluck—so consider harvesting them as you explore these areas. If you need more of these flowers to quickly Ascend a character, I recommend entering another player's World through Co-op and asking permission to farm there.
There are no Lakelight Lily seeds in the Serenitea Pot's Realm Depot, so you can't grow them in your Realm. However, after completing the World Quest "The Wild Fairy of Erinnyes," you can purchase Lakelight Lilies from Pahsiv using Tidalgas. Her store is located in the small cave north of Loch Urania.
To find more Fontaine local specialties, check out our guide on All Lumitoile locations in Genshin Impact here on Pro Game Guides.