Turtles and Tortoises are reptiles and all reptiles are considered haram according to Hanafi, Shafi and Hanbali schools. The Maliki school of thought views that all the non-poisonous/hazardous land and marine animals are Halal to consume (except for what is expressly forbidden). You can read more on Seafood Fiqh here.

You may also be interested in:

• The ruling of Seafood in Islam
• Are Scallops halal?
• Is Octopus halal?
• Are Crabs/Lobster halal?
• Is Turtle halal?
• Are Frogs halal?
• Is Squid halal?
• Are Prawns and shrimp halal?
• Is Shushi halal?
• Are Sharks and Whales halal?

You can read more on halal:

• What is Halal?: An Overview
• Importance of Halal
• General Halal Food guidelines
• The ruling of Seafood in Islam
• Halal and Haram animals according to the Hanafi School
• What parts of a Halal animal are impermissible to eat?
• Gelatine in Islam
• Animal Rennet in Islam
• Carmine in Islam
• Artificial Bacon in Islam
• Islamic Ruling of Kosher foods