Simplifying Technical Aspects Regarding Seasonality Act of 2018 or the STARS Act This bill amends the Internal Revenue Code to exclude seasonal employees from the definition of "full-time employee" for purposes of the employer mandate to provide employees with minimum essential health care coverage. The bill defines a "seasonal employee" as an employee who is employed in a position for which the customary annual employment is not more than six months and which requires performing labor or services that are ordinarily performed at certain seasons or periods of the year.