I haven't shipped any caulerpa but one of our members in New York has sent me some grape and racemosa twice. He packs it in a sealed quart size baggie of water, inside a larger baggie of water surrounded by crunched newspaper in a box. He has mailed it regular US mail which takes about 3 days to get to me. At least once it has sat on top of my mailbox in 90 degree heat until I got home from work and both times the caulerpa as been in excellent condition. The cost was $7 -$10 for shipping depending on the box size and weight. HTH