With improvised polling stations in more than 80 countries, the Venezuelan diaspora was seeking to delegitimize Maduro's plans to rewrite the constitution after three months of anti-government protests that have led to nearly 100 deaths.
Lines snaked around blocks at some polling stations in expatriate hubs like Miami, Madrid, and Bogota, where Venezuelans draped themselves in flags and shouted, 'We want freedom!'
'With this vote we want to say to Maduro that Venezuela can't wait. We want elections now. The people want him out,' said Audrey Lopez, 49, who was among volunteers staffing a polling station in the Spanish capital.
'I haven't been back to Venezuela in four years. What I save on the journey I send to my family in food, medicine or hygiene products because they are either very expensive or non-existent there,' she added.
Mitzy Capriles, wife of former Caracas mayor Antonio Ledezma who is currently in prison on charges of conspiracy, also voted in Madrid, while the father of prominent opposition leader Leopoldo Lopez cast his ballot in Rome.
'Today we are gathering peacefully to send a clear message that [the Venezuelan government] needs to listen ... and to open its eyes and see what is happening and what the people of Venezuela want,' the elder Leopoldo Lopez told reporters.
In Latin America, where ranks of Venezuelan migrants have been swelling, voters participated from Andean capital Quito to beachside Rio de Janeiro.
A New Diaspora
Official data on Venezuelans who have left is difficult to come by.
Sociologist Tomas Paez estimates some 2 million have emigrated since the late Hugo Chavez took office in 1999 and that the pace has picked up under Maduro, though government supporters dispute those figures as overblown. Caracas-based Paez has published papers and books on migration.
Nicknamed 'Saudi Venezuela' in the booming 1970s and once a magnet for European migrants, the OPEC nation is now brimming with goodbye parties and queues for passports or visas outside embassies in the capital Caracas.
Officials often ridicule Venezuelans abroad as histrionic elitists made in the same mold as the traditionally right-wing Cuban exiles in Florida.
While the early diaspora was mostly a middle-class phenomenon, recent migrants are often less economically stable due to a collapse in the local bolivar currency.
Expatriates have mobilized en masse in past presidential elections, even traveling by bus from Miami to New Orleans to cast ballots against the ruling movement known as 'Chavismo,' named after the charismatic former leader who died in 2013.
But they have faced bitter setbacks time after time.
'Ever since we left Venezuela in 2002, I knew the country would get worse with this regime, and time has proven us right, but I'm upbeat about change coming to Venezuela,' said engineer Juan Sansiviero, 41 a former employee of state oil company PDVSA, voting in Katy, Texas.
The government will hold an official vote on July 30 for a new assembly, which would be able to rewrite the constitution and dissolve state institutions.
The two elections this month are a show of force from each side. Both the government and opposition are effectively boycotting the other, hoping to legitimize themselves in the polarized environment.