A few ferry rides to Vashon Island, 1977-1978, by the dates on the slide box.
Three trips, by the look of the weather. Mid-winter. Final slide is looking back at Fauntleroy from Glen Acres, which is where I was going to, and where I moved to in June of 1979.
The sharp-eyed will notice old boats, and that the point south of the Fauntleroy dock hasn't been over-ridden by enormous McMansion mega-houses.
Other than that, not a lot has changed...
Ektachrome slides. Post-processing in Adobe Lightroom CC Classic, mostly to extend the dynamic range, pull down the blacks, and correct the color balance.