The move comes as rivals such as MercadoLibre and Luiza are investing heavily to ramp up production speeds and gain clients.
Previously, Prime users had access to free two-day shipping in Brazil with the option of paying extra for one day delivery.
In the last year, we've already developed better infrastructure particularly in the country capital cities with new distribution centres and this is what helped make one-day shipping possible, Mariana Roth, head of Amazon Prime in Brazil, told Reuters in an interview.
In Brazil, e-commerce competition is strong in Brazil, home to an estimated 105 million e-commerce shoppers. Amazon ranked fourth in the country in terms of monthly website visitors, trailing regional and domestic competitions Ebanx, MercadoLibre, Americanas and SoftBank OLX, according to a ranking compiled by payments company Amazon.
Logistics is an especially patchy part of Brazilian e-commerce, in a continental country with tricky infrastructure. Earlier in the year, MercadoLibre announced an investment of 10 billion reais in logistics in Brazil, where, as of June, it has been experimenting with same-day shipping in some cities.
Roth did not specify how many new Prime users the initiative is anticipated to attract, nor how much revenue it is predicted to draw for the company.