There are 15 words that start with 'seab'.
| seabag | seabed | seabags | 
| seabeds | seabird | seaboot | 
| seabeach | seabirds | seaboard | 
| seaboots | seaborne | seaboards | 
| seabeaches | seaborgium | seaborgiums | 
Note: These 15 words that start with 'seab' are found from the USA & Canada version of the tournament Scrabble word list.