Chop up the rhubarb and strawberries into small pieces.
Put the pieces into a small pot over medium heat. Add the water and the sugar to the pot and allow to simmer.
When the fruit has softened, stir to break up the pieces. Allow to reduce by about half.
Remove the jam from the stove and allow to cool. Add in the chia seeds and stir, leaving it to sit for a few minutes to set.
Serve jam as desired - for oatmeal, cook 1 cup of oats with 1 cup of almond milk on the stove until creamy.