Blatter was the latest international soccer figure to call into question the suitability of the US as a host country.
On Monday (Tuesday AEDT) Blatter called for the boycott in a post on X that supported Mark Pieth's comments in an interview last week with Swiss newspaper Der Bund.
Pieth, a Swiss attorney specialising in white-collar crime and an anti-corruption expert, chaired the Independent Governance Committee's oversight of FIFA reform a decade ago.
Blatter was president of the world's governing body for soccer from 1998-2015, before resigning amid an investigation into corruption.
In his interview with Der Bund, Pieth said: "If we consider everything we've discussed, there's only one piece of advice for fans: Stay away from the USA! You'll see it better on TV anyway. And upon arrival, fans should expect that if they don't please the officials, they'll be put straight on the next flight home. If they're lucky."
In his X post, Blatter quoted Pietha and added: "I think Mark Pieth is right to question this World Cup."
The US is co-hosting the World Cup with Canada and Mexico from June 11-July 19.
The international soccer community's concerns about the US stem from Trump's expansionist posture on Greenland, travel bans and aggressive tactics in dealing with migrants and immigration enforcement protesters in American cities, particularly Minneapolis.
Oke Gottlich, a vice-president of the German soccer federation, told the Hamburger Morgenpost newspaper last week that the time had come to seriously consider boycotting the World Cup.
Two weeks ago, travel plans for fans from two of the top soccer countries in Africa were thrown into disarray when the Trump administration announced a ban that would effectively bar people from Senegal and Ivory Coast from following their teams unless they already have visas.
Trump cited "screening and vetting deficiencies" as the main reason for the suspensions.
Fans from Iran and Haiti, two other countries that have qualified for the World Cup, will also be barred from entering the US. They were included in the first iteration of the travel ban announced by the Trump administration.
