Coral cover across all three regions of the Reef increased slightly or remained at similar levels to that recorded last year, indicating limited impacts from 2025’s mass bleaching event, and the regional bleaching event in the Northern and Central regions recorded earlier in 2026.

The Reef faced other impacts from flooding and two tropical cyclones including Narelle, but most of the surveys for this report were completed before its passage as a category 5 system over the Northern region in March. Increases of crown-of-thorns starfish in the Northern Great Barrier Reef over the last few years indicate initiation of the fifth recorded wave of outbreaks for the Reef since the 1960s.

The coral cover levels recorded over the 2025/26 field season were:

• Northern region (Cape York to Cooktown) increased by 16.7% relative to 2025 levels (from 30% to 35.1%)
• Central region (Cooktown to Proserpine) increased by 10.2% relative to 2025 levels (within the margin of error from 28.6% to 31.6%)
• Southern region (Proserpine to Gladstone) decreased by 2% relative to 2025 levels (from 26.9% to 26.4%, which is within the margin of error).

Coral cover levels in all three regions of the Reef continue to be above or just below the long-term average.

Percentage hard coral cover in three Great Barrier Reef regions from 1985 to 2026. Blue shading indicates uncertainty.

AIMS Long-Term Monitoring Program (LTMP) leader Dr. Mike Emslie said coral cover levels increased modestly or remained stable on many reefs and substantial declines were uncommon.

“The Reef experienced a summer of above average sea temperatures once again, but the late summer monsoon activity, which increased cloud cover and reduced sea temperatures, likely limited the severity and extent of bleaching in the 2025/26 summer,” he said.

“We did not see a repeat of the 2024 and 2025 mass bleaching events, or a repeat of the significant impacts from the 2024 event. Bleaching events vary markedly and do not always result in coral mortality. It depends on the intensity and duration of the heat stress.”

2026 is the 40th year of data for the LTMP, which provides a critical, trusted, long-term view of the Reef.

A total of 121 coral reefs were surveyed for this year’s report. Most of the reefs surveyed (106) had moderate to high coral cover (between 10% and 50%):

• only three reefs had hard coral cover less than 10%;
• 64 reefs had coral cover between 10% and 30%;
• 42 reefs had cover between 30% and 50%;
• 12 reefs had coral cover between 50% and 75%; and
• there were no reefs with cover greater than 75%.

Of the reefs surveyed, 16% showed a decline in coral cover, 56% showed no change, and 28% had an increase.

“While many reefs did not lose coral cover, bleaching likely prevented the continued increases in coral cover that would normally be expected in the absence of disturbance,” Dr. Emslie added.

The report includes a detailed examination of impacts from the 2024 mass bleaching event on different types of corals, finding shifts in coral communities not revealed by declines in total hard coral cover. In last year’s report, AIMS detailed substantial declines in coral cover from the high levels of recent years mostly due to the 2024 bleaching event.

“From our detailed surveys of permanently marked sites at 71 reefs, we found that reefs dominated by fast-growing, habitat-building, bleaching-sensitive Acropora corals were the most severely impacted by the event. The reefs with high levels of Acropora now exist in a highly vulnerable state. It’s possible that what looks like complete recovery on these reefs can be reversed in just a year,” said Dr. Emslie.

“The acute heat stress in the Southern Great Barrier Reef during the 2024 event also increased the prevalence of bleaching and mortality in reef habitats 10 to 15 m deep across most types of coral. Normally, coral bleaching mostly impacts shallow water corals because this is where sea temperatures are highest.

“Future warming trends are likely to put corals at deeper depths at greater risk of impacts from intensified coral bleaching severity and mortality as found in the Southern Great Barrier Reef in 2024.”

Dr. Emslie said that while this year’s results provided evidence of initial recovery and that coral cover levels are higher than those of many coral reef ecosystems globally, the Great Barrier Reef remained a system under pressure.

“We have seen six mass bleaching events between 2016 and 2025. Before the ’90s, bleaching events were exceptionally rare on the Great Barrier Reef. This increased frequency and escalating impact is compounded by the damage from cyclones, floods, and outbreaks of crown-of-thorns starfish,” he said.

“While the Reef is showing resilience, it is being pushed, and its capacity to recover is limited.”

AIMS CEO Professor Selina Stead said the long-term value of the 40-year-old LTMP dataset was growing in importance.

“It underpins management considerations like zoning and crown-of-thorns starfish control and provides a barometer of reef health at a time when coral reefs globally face increasing existential threats from warming oceans and other stressors,” she said.

“While evidence of recovery is encouraging, the risks for coral reefs are increasing. We can help them survive the threats posed by climate change through reducing global emissions, good reef management, and developing evidence-based science interventions that support reef adaptation and recovery.”