One time mine was packed in an extra lg suitcase, folded in half around the contents of the case. No problems. Usually, it’s packed flat in a portfolio with fabric padding on both sides. Even though the portfolio is in the sun, never a problem with warping, even the 2 weeks traveling across the country.

Have heard many stories of wrapped-ruined Matt’s with even 1/2 hr in sun.

OK, so I tried the bathtub cure, but the mat is quite large (markings are 28 x 56") and it was a pain to keep turning it in the bath.

I had more luck sandwiching the mat in an electric blanket and leaving that on overnight. It still warped very slightly as it cooled, so I will repeat the procedure tonight and put the old mat on the new one and weight that all down as it cools tomorrow.

Again, these are great mats, I am very fond of mine!

Update: all efforts to unwarp the mat have failed. I had ordered it via Amazon.ca, but I think it was either damaged in storage by a third party (stored rolled in high heat environment??), in shipping, or perhaps was a return that was resold? No idea. I have returned the mat. Thank goodness for Amazon's return policy. I have not had to use it often but this was one time it was needed.

My original MegaMat arrived with no warping once unrolled, so it seemed "off" that this one was giving so much trouble.

I have now ordered directly from Quilters Rule as they should know better than anyone how to store and ship these lovely mats.