In Virginia, it is generally mandatory for employers to carry workers' compensation insurance if they have three or more employees, including full-time, part-time, and seasonal workers. This requirement applies to all businesses, regardless of the nature of their operations or industry. However, there are a few exceptions and specific criteria to consider:

1. Sole Proprietors or Partnerships: If you are a sole proprietor or a partner in a business, you are not required to carry workers' compensation insurance for yourself. However, if you have employees, you must provide coverage for them.

2. Agricultural Employers: Agricultural employers who have more than five regular employees or ten or more seasonal workers for more than 30 days in a calendar year are required to have workers' compensation insurance.

3. Contractors and Subcontractors: In the construction industry, contractors and subcontractors must have workers' compensation insurance, regardless of the number of employees.

It is important to note that the Virginia Workers' Compensation Commission oversees workers' compensation requirements and enforces compliance. Failing to carry the necessary workers' compensation insurance can result in penalties and legal consequences.

If you are uncertain about your specific obligations or have questions regarding workers' compensation insurance requirements in Virginia, it is advisable to consult with the Virginia Workers' Compensation Commission or seek guidance from a licensed insurance professional who specializes in workers' compensation.