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.
Piece of old jean or fabric for patch
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
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.
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.