The pursuit of development in an economically sustainable and ecologically sound manner is a goal of modern society. It has been investing in products that minimize their environmental impact, particularly concerning the use of plastic. This material is highly detrimental to nature due to its toxicity and long decomposition period. The present study aims to analyze the feasibility of producing blocks made of concrete with different amounts of waste plastic taken from coastal and estuarine areas. After laboratory analysis, it was found that blocks containing 5% plastic exhibit good compressive strength and are lighter. Additionally, there was an increase in the acidity of the sample, a decrease in the density of the block, and reductions in both flexural and compressive strength. The prototype, composed of 5% plastic by mass, proves to be efficient for constructing single-story houses. It meets the minimum requirements for normative resistance, effectively encapsulating the plastic within the block and thereby reducing its environmental impact.