World Future Energy Summit – 17th to 19th
Australia Day – 26th
World Wetlands Day – 2nd
International Day of Women & Girls in Science – 11th
International Polar Bear Day – 27th
First day of Autumn – 1st
Business Clean Up Day – 1st
Schools Clean Up Day – 2nd
World Wildlife Day – 3rd
Schools Clean Up Day – 4th
Clean Up Australia Day – 6th
International Women’s Day – 8th
International Day of Action for Rivers – 14th
Green Cities Conference – 13th to 15th
Global Recycling Day – 18th
World Sparrow Day – 20th
World Planting Day – 21st
International Day of Forests – 21st
Harmony Day – 21st
Sustainable Seafood Week – 21st to 27th
World Water Day – 22nd
World Meteorological Day – 23rd
Earth Hour – 26th
National Trust Heritage Festival – 1st April to 31st May ​
World Heritage Day – 18th
World Fish Migration Day – 21st
Earth Day – 22nd
Anzac Day – 25th
International Composting Awareness Week – 1st to 7th
Walk Safely to School Day – 20th
International Day for Biological Diversity – 22nd
Greenery Day – 4th
Green Up Day – 5th
Endangered Species Day – Third Friday May
Bike-to-Work Day – Third Friday May
International Composting Awareness Week – 6th to 12th
OZWater’18 – 8th – 10th
World Parks Week – 10th to 18th
World Migratory Bird Day – 12th
National Volunteer Week – 21st to 27th
International Day for Biological Diversity – 22nd
World Turtle Day – 23rd
National Sorry Day – 26th
National Reconciliation Week – 27th to 3rd June
First day of Winter – 1st
World Environment Day – 5th
World Oceans Day – 8th
Global Wind Day – 15th
World Sea Turtle Day – 16th
World Day to Combat Desertification and Drought – 17th
World Giraffe Day – 21st
International Yoga Day – 21st
Red Nose Day – 29th

NAIDOC Week – 8th to 15th
World Population Day – 11th
Schools Tree Day – 27th
National Tree Day – 29th
International Tiger Day – 29th
Jeans for Genes Day – 3rd
International Day for World Indigenous Peoples – 9th
World Lion Day – 10th
World Elephant Day – 12th
National Science Week – 11th to 19th
International Youth Day – 12th
World Humanitarian Day – 19th
World Orangutan Day – 19th
National Honey Bee Day – 22nd
Keep Australia Beautiful Week – TBC
First day of Spring – 1st
National Biodiversity Month
National Wattle Day – 1st
Sea Week – TBC
National Landcare Week – TBC
National Threatened Species Day – 7th
National Bilby Day – 9th
Sustainable House Day – 16th
International Day for the Preservation of the Ozone Layer – 16th
World Water Monitoring Day – 18th
Bushcares Major Day Out – BMDO – TBC
Zero Emissions Day – 21st
World Car-Free Day – 22nd
World Environmental Health Day – 26th
World Maritime Day – 29th
World Habitat Day – 2nd
World Animal Day – 4th
World Space Week – 4th to 10th
All Energy 2018 conference – 3rd to 4th
National Walk to Work Day – 5th
National Ride 2 Work Day – TBC
International Day for Disaster Reduction – 13th
World Food Day – 16th
International Day for the Eradication of Poverty – 17th
Bird Week – TBC
Aussie Backyard Bird Count – 22nd to 28th
National Water Week – TBC
United Nations Day – 24th
International Day of Climate Action – 24th
World Day for Audiovisual Heritage – 27th