A quiet, lonely meal is at the center of this tiny poem. The speaker is eating food straight from a can, which suggests a simple, makeshift supper with no one to share it. The title, "Dinner date," turns that image a little sad and a little funny. A dinner date is usually something romantic or social, but here the only companion is the sound of the sea at night.
The second line is the heart of it: the speaker listens "for company's sake." That phrase admits a bit of loneliness, but it also shows a gentle way of coping. The waves become a kind of guest at the table, steady and always there. Judging by the imagery, the speaker may be somewhere remote or just on their own for the evening.
The mood is hushed, wry, and calm. There is some melancholy, yet also acceptance, even comfort, in letting the dark, endless sound of the water keep you company.