Climate change is a global issue, caused by increased levels of carbon dioxide in the atmosphere resulting in many adverse effects. One of the many responses to the climate change impact is to sequester carbon dioxide from the atmosphere. Al-Qurm Nature Reserve in Muscat city of Oman is a mangrove vegetation protected by law as conservation area. Carbon sequestration was estimated in three distinct zones of this natural mangrove vegetation with Avicennia marina. The mean carbon stock in the middle zone was 7.7±0.3 kg C/m2, and for the seaward zone was 5.3±0.7 kg C/m2, and for landward 18.8±0.1 kg C/m2, which is 3.5 times higher than seaward zone and slightly more than 2 times than middle zone. The 0.82 km2 of Al-Qurm Nature Reserve occupied purely by Avicennia marina was estimated to sink about 8692 t C (0.0087 Mt C) equivalent to about 0.032 Mt of CO2e. These estimates suggest a high carbon storage and carbon sequestration potential of Avicennia marina in Al-Qurm Nature Reserve despite their relatively small area.