Sometimes the hole in your jeans is not meant to be there. While this a patch is still visible it is a very strong patch and less noticeable than and outside patch.
Tools:
Scissors
Sewing machine
Pins
Materials:
Piece of old jean or fabric for patch
Thread
Lets get started
Rip side seam open. Do not touch the double seamed hem. Leave yourself enough room to fit your work under the needle ( about 6” or a bit more if they are skinny jeans)
Cut away frying fabric.
Cut patch from desired fabric 1” beyond on all 4 sides.
Pin in place
Find a thread that will compliment the jean color, because you will see the stitching.
Straight stitch close to the edge all 4 sides. Be sure not to catch the pant leg wile you are working through the side seam.
This is how it will look after sewing.
Trim away excess on the back, leaving 1/4” all sides.
From the right, stitch back and forth repeatedly to cover the raw edge completely. If you have a darning stitch use it here.
The last step is to resew the side seam closed while the leg of the pant is inside out. Now they are ready to wear.