Ive seen some amazing stateroom doors for big anniversary numbers. Like pics of the couple from their wedding laminated on the door, etc. You can tell the family went all-out. It was sweet. When we did my boys’ graduation cruises (literally, we homeschooled so graduation was ON the cruises) I got some magnetic clips like
these and attached a big garland over our stateroom door. It was really festive! You can also use the magnetic clips to decorate inside the room. The magnets hold to the walls, ceiling, etc. Just no balloons.
Another idea is to find a button-maker on Etsy to make special custom buttons they can wear.
I should get with it on decor ideas for my own stateroom door in September. Will be celebrating 25 yrs. Your parents are —> #goals.
Oh! And something I surprised hubby with several anniversaries back. Silly and small but it was sentimental and meant so much to him at the time. While we did do Palo which is when I surprised him, I think you could do it at the family table. I brought our little ceramic cherub that sat on top of our wedding cake, one of our leftover invitations, and a leftover cocktail napkin that had our custom printing on it. (Yeah, it was the cheesy 90s.) When we got to dinner I took these things from my little handbag and placed them on the table as a centerpiece. He was so surprised...and I made him all sentimental and teary. If your parents don’t have things like this, why not make them up and set a “wedding table” for them? Order a specialty cake and place a Mickey & Minnie topper on it. There’s a ton you can do!