The MSC Oscar is shorter in length than the CSCL Globe but can carry more containersMSC Oscar is shorter in length than the previous holder the CSCL Globe, which docked in Felixstowe in January, but can carry 124 more containers.
It is 396m (12,999ft) long and has a capacity of 19,224 standard containers.
Clemence Cheng, chief executive of Port of Felixstowe, said it was a "very happy day" for the port.
More than 200 people welcomed the ship's arrival, at about 11:30 GMT.
The Port of Felixstowe said MSC's continued use of Felixstowe was a "seal of approval"
The MSC Oscar had sailed to Felixstowe from Holland
The MSC Oscar is docked at berths eight and nine
It had sailed from Rotterdam and its stop in Felixstowe is the last before it returns to Asia.
Mr Cheng said MSC had worked with the port for the past 30 years and that its continued business, despite the added option of London Gateway, was a "seal of approval".
"We're giving them the service that they want," he said. "It's good for the port, good for Suffolk and good for the country."
World's biggest container ship MSC Oscar arriving at Port of Felixstowe.
Weighing in at almost 200,000 tonnes, the MSC Oscar is being greeted with a special reception by port officials.
With its 395.4-metre length, 59m width and 16m draught, the Korean-built ship became the world’s largest earlier this year – edging out its predecessor, the CSCL Globe, which arrived at the port in January.
Hundreds of ship-spotters are expected at Landguard peninsula to get a glimpse of the ship on its latest stop on a tour of Europe, having already called at Algeciras, Spain, Rotterdam, Bremen and Wilhelmshaven, Germany.
The Oscar, owned by the Mediterranean Shipping Company (MSC), which has its UK headquarters at The Havens, Ipswich, was launched on January 8 and is named after the son of MSC president and chief executive Diego Aponte.
It was built by Daewoo Shipbuilding and Marine Engineering at a shipyard near Busan, South Korea.
Weighing in at almost 200,000 tonnes, the MSC Oscar is being greeted with a special reception by port officials.
