This is a slightly modified version of the origami swan designed by Stephen Weiss. The original requires double sided paper, but this version adds a few extra steps to the tail and neck to allow one sided paper. The original diagrams are published in his book Origami Zoo and there is also a YouTube video tutorial. The design can be packed flat if you're not too particular about the shaping of the head neck and tail.
One square piece of origami paper. If you have a colored side and want the swan to be that color, position the colored side as I've positioned the green side of my paper in these pictures. No special tools are required except for your fingers. I used 15x15cm paper.
Step 1: Basic Body Shape
Follow the photos to form the basic body shape of the swan.
Step 2: Wing Tip
Shape each wing tip with one fold.
Step 3: Wings
Follow the picture to create the wings. Turn over and flatten.
Step 4: Tail
Form the tail.
Step 5: Color Neck
Reverse folds to make the neck colored instead of white.
Step 6: Shape Neck and Head
Make the shape of the head and neck using outside reverse folds.
Step 7: Make Head Bigger
Open up the cheek of the head to make the swan head bigger. Flatten the back of the head so that it can lie flat.
Step 8: Make Beak
The shape of the beak is made with an inside reverse fold followed by an outside reverse fold.
Step 9: Add Neck Bend
The iconic swan neck bend is also made with an inside reverse fold followed by an outside reverse fold.
Step 10: Thin Neck
That's the last step. Enjoy your swan. :) Now you are equipped to fold a whole flock!