The due dates for day laborer contributions are September 30 and March 31.
日雇拠出金の納期は、九月三十日及び三月三十一日とする。
The amount of day laborer contributions to be paid on each due date is the amount equivalent to one-half of the amount of day laborer contributions for the relevant fiscal year pursuant to Article 174 of the Act.
Notwithstanding the preceding paragraph, where the amount of day laborer contributions for the fiscal year has a fractional amount of less than 2,000 yen, the amount to be paid on the due date of September 30 is the amount equivalent to one-half of the amount obtained by adding that fractional amount to the amount of day laborer contributions for that fiscal year, and the amount to be paid on the due date of March 31 is the amount equivalent to one-half of the amount obtained by deducting that fractional amount from the amount of day laborer contributions for that fiscal year.
略称規定第二十条第一項
健康保険組合は、保険給付に要する費用（高齢者の医療の確保に関する法律（昭和五十七年法律第八十号）の規定による前期高齢者納付金等（以下「前期高齢者納付金等」という。）、同法の規定による後期高齢者支援金、後期高齢者関係事務費拠出金及び出産育児…
わかりやすく言うと
日雇特例被保険者に係る健康保険事業の費用に充てるため、厚生労働大臣が毎年度、日雇特例被保険者を使用する事業主が設立した健康保険組合などから徴収する拠出金のことです（健康保険法第百七十三条）。