Preheat oven to 400 degrees Fahrenheit (204 degrees Celsius).

Rinse the chickpeas under cold water and drain thoroughly.

Place chickpeas on a clean kitchen towel and pat dry until all surface moisture is removed.

In a medium mixing bowl, toss the dried chickpeas with olive oil, sea salt, garlic powder, and crushed rosemary until evenly coated.

Spread the chickpeas in a single layer on a large rimmed baking sheet.

Roast for 30 minutes, shaking the pan every 10 minutes to ensure even browning.

Remove from oven and allow to cool completely on the baking sheet to achieve maximum crispness.