Astiazaran is making his first Championship start in 2026. In 2025, the Vanderbilt University junior won both the Mexican Amateur and North and South Amateur Championships and represented his country in the Eisenhower Trophy in Singapore. In 2023, he won the Boys 15-18 division of the Junior World Championships in San Diego. Notable winners of the North and South Amateur include Francis Ouimet, Jack Nicklaus and Curtis Strange, while notable winners of the oldest age division in the Junior World Championships include Nick Price, Tiger Woods and Joaquin Niemann.