7 AprilPayroll tax returns due21 AprilMonthly BAS for Mar 2026 due28 AprilQuarterly BAS for Q3 (Jan–Mar 2026) dueSuper guarantee payments for Q3 due30 AprilR&D Tax Incentive claims due for FY 2025–26Note: If ATO due date falls on a weekend, the due date is the next business day.