There are a variety of synonyms for the phrase "along a coast." Some options include the phrase "coastal" or "coastline," both of which have a similar meaning and can easily be substituted in place of the original phrase. Another option might be "seaside," which is a bit more specific to the idea of being near the ocean or sea. Additionally, you could use words like "shoreline," "beachfront," or "water's edge" to convey a similar idea. Ultimately, the right synonym for this phrase will depend on the context and tone of your writing, but these are all great options to consider.