formal night

Can my husband wear a sport coat with pants, shirt and tie on formal night. I don't want to buy a new suit just for the cruise.

[LobsterLady]

You can rent a Tux from the cruise ship. You will find the # in your brochure or in with your documents.
Also there are shirts you can buy to make a suit look more formal. Gentilmans Wear House is a good place to start.
By all means do not buy a Tux. Mens weight changes (though they won't admit it ever). We have been on 4 cruises and we have found my husbands light colord suit jacket with a no-collar shirt and button cover pin looks very formal.
Good luck. And have fun.