Tatiana "Tati" Guimarães Weston-Webb (born May 9, 1996) is a Brazilian surfer based in Kauai, Hawaii. She is also both American and English. She was the only rookie on the professional surfing World Championship Tour in 2015. Weston-Webb wears jersey number 9, and her 2016 'CT rank is number 4. She competed in both the 2020 and 2024 Summer Olympics for Brazil, winning silver in the latter and because of that she became the first woman surfer from Brazil to win a medal at the Olympics.
Weston-Webb's father, Douglas Weston-Webb, was born in England, a descendant of a family engaged in the textile business. The Weston-Webb name is a heritable double-barrelled surname, created through the marriage of two children from significant families in that industry. He moved at an early age to the U.S. state of Florida, where he was raised. He learned to surf at age eight and later became a "surf bum" and relocated to Kauai in his 20s.
Weston-Webb's mother, Tanira Weston-Webb (), was a Brazilian professional body boarder, under sponsorship by two industry companies. Tanira's sister, Andrea Guimarães, was also a bodyboarder.
Douglas and Tanira met while she was in Hawaii. They moved to Brazil, where Tatiana was born in 1996, in Porto Alegre. Because of her father's birth in the United Kingdom, Tatiana also automatically acquired British citizenship by descent at birth. However, she has not applied for a British passport, and her father has not renewed his in many years.
Within two months of her birth in Brazil, Weston-Webb and her parents moved to Hawaii. At age 8, while watching her older brother Troy surf, Tatiana decided to take up the sport as well. Surfing became a competition between the children, and Tatiana received her first surfboard soon afterward.
In 2011, she played 11-year-old Bethany Hamilton in the film Soul Surfer.
In 2020, she married longtime boyfriend Jessé Mendes dos Santos, a Brazilian fellow professional surfer from Guarujá, São Paulo, who competes under the name Jessé Mendes. The pair married in an intimate beachfront ceremony held at the Princeville Resort, a Kauai hotel her father had worked at for many years, after the security guard allowed them to use the otherwise expensive site at no cost during the property's renovation.
In 2015 Weston-Webb secured a spot in the World Championship Tour.
On April 29, 2018, she announced her switch to Brazil representation for the remainder of the 2018 WSL Championship Tour season, aiming to compete representing her native country in the 2020 Summer Olympics in Tokyo, one of her dreams since surfing was announced as an official Olympic sport. Weston-Webb ended her Tokyo campaign in the round of 16. In the 2024 Summer Olympics, Weston-Webb reached the final, and only lost the gold to world champion Caroline Marks by a score of 0.18.
On March 27, 2025, Weston-Webb announced she was taking a break from the World Championship Tour for mental health reasons.