| Y1 – IB1 School Camp | 03 Jan – 04 Jan |
| IB Results Release | 03 Jan |
| Y1 Induction Ceremony | 10 Jan |
| IGCSE Results Release | 16 Jan |
| Chinese New Year Celebration | 24 Jan |
| Lo Hei Lunch | 03 Feb |
| E-Learning Day | 13 Mar |
| HCIS Model United Nations | 26 Mar – 27 Mar |
| IB2 Parent-Teacher Interaction | 17 Apr |
| IB2 Mid-Year Examinations | 29 Jun – 03 Jul |
| Y1 – IB1 Standardised Assessments | 29 Jun – 09 Jul |
| Economics Day | 13 Jul |
| Y1 – IB2 Parent-Teacher Interaction | 06 Aug |
| HCIS Gives Back | 07 Aug |
| The Voice of HCIS | 13 Aug |
| Y4 (IGCSE) Preliminary Examinations | 19 Aug – 02 Sep |
| IB2 Preliminary Examinations | 31 Aug – 02 Sep, 14 Sep – 24 Sep |
| Teachers’ Day Celebration | 03 Sep |
| IB1 End-of-Year Examinations | 14 Sep – 25 Sep |
| IB Graduation Ceremony | 09 Oct |
| Y4 (IGCSE) Examinations | 09 Oct – 17 Nov |
| IB Examinations | 26 Oct – 13 Nov |
| Y1 – Y4 End-of-Year Examinations | 26 Oct – 06 Nov |
| IB1 CAS Trip | 30 Oct – 06 Nov |
| Examination Marking Day | 09 Nov – 10 Nov |
| Examination Admin Day | 12 Nov – 13 Nov |
| InnoFest | 18 Nov |
| IB Results Release | 04 Jan 2021 |