Leatherback sea turtle by Michael G. LaFosse

Diagrams in LaFosse and Alexander's Essential Book of Origami by Michael G. LaFosse and Richard L. Alexander
Wet Folded from a square of art paper

Pond turtle by Michael G. LaFosse

Diagrams in Origami Art by Michael G. LaFosse and Richard L. Alexander
Wet-folded from a square of Elephant-Hide

Sea turtle by Arun Soor

Diagrams in Christmas Origami Book 2010
Folded from a square of bubble-texture origami paper

Turtle by John Szinger

Diagrams in Origami Animal Sculpture by John Szinger
Diagrams in Zing Origami by John Szinger
Diagrams in Origami USA Convention 2008
Wet-folded from a square of Unryu paper

Turtle 8 by Juan Gimeno

Diagrams in Pajarita Extra 2021 - 40th Anniversary of AEP
Diagrams in El Libro de Las Pajaritas de Papel by Grupo Riglos
Diagrams in Das Diagramm 41
Folded from a rectangle of patterned foil

Tortoise by Jun Maekawa

Diagrams in Genuine Japanese Origami (Book 1) by Jun Maekawa
Diagrams in Genuine Origami Square-Root 2 by Jun Maekawa
Folded from a rectangle of scrapbooking paper

Tortoise by Lionel Albertino

Diagrams in MFPP Collection - Volume 1 - Origami Gourmand
Diagrams in Safari Origami by Lionel Albertino
Wet-folded from a square of 160gsm Canson paper

Turtle by Robert J. Lang

Diagrams in A Arte dos Mestres de Origami by Mari Kanegae
Diagrams in Origami Animals / Paper Animals by Robert J. Lang
Diagrams in Origami Design Secrets - 2nd edition by Robert J. Lang
Diagrams in The Encyclopedia of Origami and Papercraft Techniques by Emma Callery
Folded from a square of "Vietnamese wrapping-paper"

Turtle by Akira Yoshizawa

Diagrams in A Arte dos Mestres de Origami by Mari Kanegae
Diagrams in Akira Yoshizawa - Japan's Greatest Origami Master by Akira Yoshizawa
Diagrams in Akira Yoshizawa Origami - Exhibition Catalog by Akira Yoshizawa
Diagrams in Beautiful Origami by Akira Yoshizawa
Diagrams in Origami Journal (Russian) 14 1998 4
Folded from a square of shizen handmade paper

Turtle by Beth Johnson

Folded from a hexagon of Kraft paper