Prepare all ingredients before you start cooking. Peel and devein the shrimp, wash and slice the vegetables, and mince the garlic and ginger.
Heat the vegetable oil in a wok or large skillet over medium-high heat.
Add the minced garlic and ginger to the pan and stir-fry for about 30 seconds until fragrant.
Add the shrimp to the skillet and cook for approximately 3-4 minutes, or until they turn pink and opaque. Remove the shrimp from the pan and set aside.
In the same skillet, add the sliced bell peppers, broccoli florets, and snap peas. Stir-fry the vegetables for about 4-5 minutes until they are tender but still crisp.
Return the cooked shrimp to the pan and stir in the soy sauce, oyster sauce (if using), black pepper, and salt. Mix well.
Add the cornstarch mixture to the pan and stir until the sauce thickens, about 1-2 minutes.
Serve the shrimp veggie stir-fry hot over steamed rice if desired.