In a large sauté pan, heat the oil to medium, sauté the shrimp for 1 minute and then set aside for later. Add the onions, and garlic and cook till onions are translucent
Stir in the Sazón and the seasoning. Add the uncooked rice and sauté for 1 minute. Add water and bring to a rapid boil, gently shaking and turning the pan so all ingredients heat evenly.
Reduce Heat to a gentle boil and simmer until most of the liquid has been absorbed. Stir gently and cover.
Add peas and seafood. Simmer until rice is done to desired consistency.
Remove from heat and garnish with thin slices of pimientos.