Remove the shell from the shrimp, devein, wash, and drain. I used medium-sized shrimp. Pour in the lime and lemon juices and stir.
Marinate in the fridge for 60 to 80 minutes. They will firm up and go opaque in color.
In the meantime, prepare the other ingredients. I suggest that you dice the mango and avocado into similar-sized pieces. Try to get a half-ripe mango, meaning it's not fully ripe but mature. Once peeled and diced, it will be firm and sweet with a slight tartness.
Remove the marinated shrimp from the fridge and add all of the other ingredients.
Stir well to combine all these fresh flavors.
Chill for another 10 minutes, then serve.