A trail of small black ants crossing a pale timber kitchen bench in a Sydney home

Types of Ants in Sydney: How to Identify Them and Get Rid of Them

7 November 2026By Jashlin Pest AdminAnts

The ant on your kitchen bench is not the same as the one in the garden. Here are the main species around Sydney, where they nest, and what actually works.

A line of small black ants on the kitchen bench is easy to treat as one problem. In Sydney it can be several. Black house ants, sugar ants, Argentine ants, coastal brown ants and Pharaoh's ants look similar at a glance and behave differently. The species decides where the nest is, what bait works, and whether a spray will help or make things worse.

This guide covers the ants you are most likely to meet around a Sydney home, how to tell them apart, and what to do next.

Quick check: what you are looking at

Small black ants in a steady kitchen trail: black house ant.
Large ants with an orange-brown middle and black head and abdomen: sugar ant.
Tiny, slender brown ants in a slow, wide trail: Argentine ant.
Tiny light-brown ants with several sizes in one trail, including big-headed soldiers: coastal brown ant.
Metallic green-blue ants, 5 to 7 mm long: green-head ant.
Large ants, 8 to 40 mm, with big eyes and a painful sting: bull ant.
Tiny yellow-brown ants indoors, often near warmth: Pharaoh's ant.

The species that matter in Sydney homes

1. Black house ant

Black house ants are native to Australia and are one of the most common ants around homes and schools. They are small and black, and they nest in trees, dry logs, hollow stems, soil spaces and buildings.

They are attracted to sweet food, which is why they turn up on benches, in pantries and around pet bowls. A trail along a kitchen wall often leads to a nest in a wall cavity or under a skirting board.

2. Sugar ant

Sugar ants are larger, 5 to 15 mm, with an orange-brown middle and a black head and abdomen. They are also called banded sugar ants.

They feed on sweet food, nectar and honeydew, and they forage under street lights and house lights in summer. They usually nest in soil, under rocks or in rotting timber, and they are more of a garden and outdoor ant than a serious indoor pest.

3. Argentine ant

Argentine ants are introduced. They are slender, brown and 1.5 to 3 mm long, with no soldier caste, so every worker in the trail looks the same size.

They are difficult because they have multiple queens and interconnected nests. A single infestation can cover several hectares. They travel in slow, well-defined trails up to three ants wide, and they climb over just about anything in their path.

Argentine ants prefer sweet food, especially honeydew, but they will also eat meat and dead insects. They nest outside in tree bases, along building edges, under paths and in lawns, and they move indoors in wet weather. Because the colony is spread across the property, spraying one trail often pushes the ants somewhere else.

4. Coastal brown ant

Coastal brown ants, also called big-headed ants, are introduced. Workers are 1.5 to 3 mm long and shiny light to dark brown. Soldiers are larger, 3.5 to 4.5 mm, with oversized heads and powerful jaws.

They have multiple queens and nests with many interconnected holes. They nest around paths and rockeries, and in heavy infestations they move into wall cavities and behind skirting boards. They prefer protein and grease, such as dead insects, meat and pet food, rather than sugar alone.

One visible sign is a small pile of loose sandy soil along a path, driveway or skirting board. It can look like termite activity, but coastal brown ant soil is loose and the tubes are fragile.

5. Green-head ant

Green-head ants are native, 5 to 7 mm long, with a metallic green, blue or purple sheen. They are one of the most abundant and widespread Australian insects.

They forage during the day on the ground and among vegetation. They can sting if handled or disturbed, but they are not usually a kitchen pest. If they are in a garden bed away from the house, they are doing useful work.

6. Bull ant

Bull ants are large, alert ants that can reach 40 mm. They have large eyes, long mandibles and a venom-loaded sting. About nine species have been recorded in Sydney, and some smaller species are known as jumper ants.

They nest in soil and defend the nest aggressively. They can track and follow a person from about a metre away. If you find a bull ant nest near a path or play area, keep away and call a professional.

7. Pharaoh's ant

Pharaoh's ants are tiny, 1.5 to 2 mm, and light yellow-brown to darker brown. They have multiple queens and can build very large colonies.

They nest in warm parts of buildings: wall voids, behind skirting boards, near heating ducts, in roof voids, bathrooms and kitchens. They prefer high-protein food such as meat, fats and dead insects, but they will also take sweets.

The important thing about Pharaoh's ants is what not to do. Spraying them causes the colony to split or "bud", which can create new nests and make the infestation worse. Baiting is the effective method.

Why ants keep coming back

Most DIY ant treatments kill the ants you can see. The colony is usually somewhere else: under a slab, in a wall cavity, behind a skirting board or in a garden bed.

Ants also leave pheromone trails. Even if you wipe out the workers on a bench, the trail remains, and new foragers follow it back.

Some species make this harder. Argentine, coastal brown and Pharaoh's ants have multiple queens and interconnected nests. A spray that kills one group can split the colony and spread it.

Food and moisture keep the cycle going. Crumbs, pet food, open bins, dripping taps and condensation around dishwashers all give ants a reason to come back.

What actually works

Treatment starts with identification. A bait that works on a sugar-feeding black house ant may not interest a coastal brown ant looking for protein. A spray that works on a single-queen species can make a multi-queen species worse.

The next step is finding the nest. Follow the trail back from the food source, check along edges, under paths, in wall cavities and behind skirting boards. The nest is usually close to the food and moisture.

Direct nest treatment is the most effective option where the nest can be reached. For species that are hard to reach or prone to budding, baiting is the better choice. A perimeter barrier around the exterior helps stop new foragers, but it has to be applied properly and re-applied after heavy rain.

Clean up food and moisture at the same time. Treatment buys you time; hygiene and exclusion keep the ants from coming back.

When to call a pest controller

Call a professional if the trail keeps returning after you have cleaned and sprayed, or if you are seeing ants in wall cavities, roof voids or under slabs.

Call sooner if you see several sizes of ant in one trail, because that often means a multi-queen species such as coastal brown or Pharaoh's ant. If anyone in the house has an ant or insect sting allergy, do not wait.

A professional treatment is also the practical choice for a rental, a strata building or a food business, where you need a documented scope and a follow-up.

Jashlin Pest Control treats ant nests across Sydney, including hard-to-reach nests in walls and under slabs.

How to prevent ants

Seal gaps around doors, windows, pipes and wall penetrations.
Store food in sealed containers and wipe benches after meals.
Rinse pet bowls and keep dry food sealed.
Fix leaking taps, gutters and air-conditioner condensate.
Keep mulch and soil below the slab edge and weep holes.
Remove stored timber, boxes and clutter from against the house.
Check pot plants and indoor plants for nests in the soil.

Frequently asked questions

Are ants dangerous?

Most common Sydney ants are a nuisance rather than a health threat. Some, such as bull ants and green-head ants, can sting. Pharaoh's ants can carry bacteria in hospitals and food premises, which is why they are treated seriously in commercial settings.

Why do ants come back after spraying?

Because the nest survived. Surface sprays kill the workers that walk over the treated area, but the colony keeps producing more. For multi-queen species, spraying can also split the colony and spread it.

What is the best ant bait?

The one the species will actually take. Sugar-based baits work for black house ants and Argentine ants; protein or grease-based baits work better for coastal brown ants. The bait needs to be placed on active trails, not heaped in one spot.

Do I need to treat the whole yard?

Sometimes. Argentine and coastal brown ant infestations can cover a whole block, and treating only the visible trail often leaves the colony intact. A professional inspection determines the boundary.

How long until the ants are gone?

Baiting takes days to weeks because the workers have to carry it back to the colony. A direct nest treatment can work faster. Either way, expect to check the area again after a week or two.

Where this information comes from

If ants keep coming back, book a free quote or call 0450 795 797.