- Oakhurst to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oakville to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oatlands to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oatley to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Old Guildford to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Old Toongabbie to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oran Park to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Orchard Hills to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oxford Falls to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oxley Park to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Oyster Bay to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Sydney Airport to Castlereagh Boutique Hotel, Ascend Hotel Collection Member
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oakhurst
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oakville
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oatlands
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oatley
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Old Guildford
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Old Toongabbie
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oran Park
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Orchard Hills
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oxford Falls
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oxley Park
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Oyster Bay
- Castlereagh Boutique Hotel, Ascend Hotel Collection Member to Sydney Airport