The answer depends on historical framing:
- By sea (European perspective): Portuguese explorer Vasco da Gama was the first European to reach India by sea, arriving at Calicut (Kozhikode), Kerala on 20 May 1498 via the Cape of Good Hope route
- Overland (ancient): Persia, Greece, and Central Asia had contact with India long before European sea routes, Alexander the Great reached the Indian subcontinent in 326 BCE
- Columbus's error: Christopher Columbus (1492) was searching for India when he reached the Americas leading to the term "West Indies"
- India was never "undiscovered" it had continuous civilization since the Indus Valley Civilization (c. 3300 BCE)
In school-level context (European maritime exploration): The answer is Vasco da Gama (1498).