In a blender, layer the ingredients exactly as listed. Blend on medium until completely smooth. About 1-2 minutes. Transfer to a mason jar and drink.
Notes
To make this colder, use frozen blueberries.
The blueberry spinach smoothie will thicken over time because of the chia seeds and oats. Even though it jiggles like jello a bit, it is still easy to drink with a straw.
For a dairy-free smoothie see the notes in the post.