I would quilt the entire piece first because quilting after cutting will make your pattern pieces smaller. You lose a little length & width with quilting.

I agree with awesome, quilt first

Hmmm, I would say it would depend upon what type of quilting and designs you were thinking about using...If I wanted an "all over quilted look" and you wanted your quilting to also be caught in the seaming, I would quilt first...but if I had specific decoration designs I wanted, I would possibly construct the jacket and embroider/quilt it after...I have done both...it could also depend upon the pattern you choose to use...Probably not much help...but I have done both...and sometimes I have done the "background quilting"...constructed the jacket...and then done the decorative quilting after the construction is complete...lots of variables...

First as if you cut out and then quilt it will get smaller. I can tell you this from first hand experience many, many years ago

I found this an interesting question. I make casserole covers and quilt the piece first as I have found no matter how much you tack it will always move a little and you will find it could be smaller than you thought it would be. After quilting I cut out the shape that I need.

Quilt the fabric first and remember that it will be smaller when you have!

I would quilt first but if you find that too hard as one big piece you could cut the jacket a size larger.

You would absolutely quilt your fabric first and then cut out the pattern pieces!!!!!! Ginny in Ft. Myers

Depending on the amount of fabric you have ,you could quilt the pieces individually .If you do it this way think about these points-do you need to match stripes ,checks or some design.For a front jacket piece I would cut a rectangle piece a least 3" larger that the pattern which would probably still be bigger than needed but the more quilting you do the smaller the fabric becomes & it is easy to cut the excess off.
Don't forget to show us the jacket.

Quilt first. The sewing of the quilting will pull the fabric slightly, making the fabric to 'shrink' a little. Please let us know how you get on.

Thanks everyone for really helpful suggestions. I did have it in mind to cut out the largest size from the pattern which is 1-2 times too big. I didn't want to quilt all the material really as I may need some for bias binding but will see how it goes. Watch this space.

Hi Gill, I do a lot of quilting and I would certainly quilt my material first, then lay the pattern on it and cut it out. You get a lot of shrinkage when quilting. I hope you have a huge success with it. Love Chris

Great answers! I had no clue till I read the answers. I thought cut then quilt to save material, but after reading, think I would quilt first then cut to prevent headache....HA!!!

Very good points to consider. Would love to see your jacket when you are done

as Sue says, quilt first because then you can cut your pattern out and it will be the correct size.

My experience has shown me that I should cut an extra large cloth to quilt first and then cut out using the pattern. I'd really use like twice the size of fabric to quilt to be sure to get a sample to use with the pattern. now, I should have read what others have said below so I'm not uniquely wrong. Lol