Fashion expert Donny Galella estimated the dress to be worth more than $2000 and noted that Meghan paired her outfit with "sensible" wedge shoed.
He told New Idea, "Meghan chose a long maxi dress by Martin Grant. It suits the beach vibes and bold vertical stripes are really trending at the moment."
Martin Grant was born in Melbourne and launched his first ready-to-wear collection at the age of 16.
He was quickly recognised by the Australian fashion industry and was named Cointreau Young Designer of the Year at the age of 20.
After a brief period studying sculpture at the Victorian College of the Arts, Grant established his studio in Paris and produced his first runway show in the heart of the Marais district. It was during this time that supermodel Naomi Campbell made a surprise appearance modelling Grant's collection.
Over the years, Grant has created his own house and developed a network of private clients and loyal international buyers. His silhouettes stand out for their pure lines that are both simple and spectacular.
Grant's work reflects his refined understanding of structure and volume. Each garment is constructed in such a way as to maintain a direct relationship to the body as a sculptural form.
In 2005, the National Gallery of Victoria held an exhibition celebrating Martin Grant's work and achievements. The show highlighted the elegance and uncluttered modernity of his designs.
Recently, Australia's national airline, Qantas, called on Martin Grant to design the company's new uniform.
Australian supermodel Miranda Kerr unveiled the collection at a runway show in Sydney earlier this year before the uniform rolls out globally in 2014.
The couple have been given leis and both Harry and Meghan took off their shoes as they stepped onto the sand.
The Duke and Duchess of Sussex will meet OneWave, a local surfing community group, and will take part in Fluro Friday.
Members of the group are wearing colourful leis for the session which encourages discussion of mental health issues.