To miss the boat means to lose out on a chance or opportunity due to not taking action fast enough. This is a popular idiom used in social and professional contexts.

1. Tickets for the match went on sale last week, but I missed the boat by waiting until today to try and buy one because now they're all sold out!
2. I missed the boat on signing up for the trip. All the spots were gone when I went to put my name down.

1. I told Katie that if she didn't put herself forward for the vacant managerial role then she would miss the boat. That opportunity may not come around again.
2. You missed the boat by not selling your shares in the company last month. Their share price hit a record high!