A man has pleaded guilty to multiple charges connected to a fatal crash in Western Australia's Midwest that claimed the lives of a baby and two women in August 2024.

Nathaniel Jackman was due to face a trial in the Geraldton District Court but entered guilty pleas to charges relating to the crash. The case concerns a Toyota Hilux that rolled on the Geraldton-Mt Magnet Road near Yalgoo, about 500 kilometres north of Perth.

The crash happened shortly before 11pm on August 10, 2024, when the vehicle was carrying six people. A weeks-old baby, Levi Ashwin, died at the scene. Gabrielle Brockman, aged 21, also died as a result of injuries sustained in the crash. The baby's mother, Marrika Brockman, later died in hospital.

Other passengers were seriously injured and required medical treatment following the rollover.

The court heard the vehicle had travelled onto the wrong side of the road and onto the roadside verge before the driver attempted to correct its direction. Several passengers were ejected during the rollover.

Prosecutors told the court that Jackman did not hold a valid driver's licence at the time of the crash. The court also heard evidence that he had cannabis in his system when the incident occurred.

The prosecution case included concerns about the number of passengers in the vehicle and the circumstances surrounding the driving shortly before the crash.

Jackman's defence lawyer presented a different account of how he came to be driving the vehicle. The defence told the court that Jackman had initially been reluctant to drive and had felt pressured to take control of the vehicle after another passenger had driven a significant distance.

The guilty plea brought the planned trial to an end and means the court will now move toward sentencing.

The case has highlighted the serious consequences that can follow when multiple road-safety risks occur together, particularly on long regional roads where distances between towns and emergency services can be significant.

The fatal crash occurred more than two years ago, but the court proceedings have continued as investigators, prosecutors and the families involved worked through the legal process.

Jackman is expected to return to the Geraldton District Court for sentencing next year. Before sentencing, the court is expected to consider relevant reports and submissions from both the prosecution and defence.

The guilty pleas establish Jackman's responsibility for the offences to which he pleaded guilty, while the final sentence remains a matter for the court.

The deaths had a lasting impact on the families and communities connected to those involved. The sentencing process will provide the court with an opportunity to consider the circumstances of the crash, the offences and the consequences for the victims and their families.