Without minaret or dome, the beige, rectangular structure in a former industrial area has none of the ornate grace typical of Islamic places of worship.
But for the Muslims of Athens, it is the result of a long-fought battle – and the city's first formal mosque in more than 180 years.
Greek authorities said on Friday that Athens would open its first official mosque probably by September when the 850,000 euro construction project is completed.
Although there are mosques in other parts of Greece, the capital has not had a formal mosque since it drove out occupying Ottomans in 1833, and the few that are left have been repurposed.
Plans to build a mosque began in 1890 with an act of parliament, but all fell through, including one timed for the 2004 Olympics.
"Soon the first prayers will be made by the imam.. We hope that can take place by September," Education Minister Kostas Gavroglou told journalists.
Stymied by red tape, a financial crisis, a predominantly Christian Orthodox population and opposition from the rise of the far right of the country, getting approval for the mosque took years, forcing Muslims to pray at makeshift sites dotted across the city, ranging from crowded basements or dark warehouses.
"This is like a dream come true," said Ashir Haider, a spokesman for the Shi'ite Muslim community of in Athens.
More than 200,000 Muslims from countries including Pakistan, Syria, Afghanistan and Bangladesh live in the Greek capital, according to Muslim groups. Greece has its own Muslim community which represent about 2 percent of the population who live mainly in the north where they have their own mosques.
Efforts over the years to build a mosque in Athens sparked protests from fringe groups on the far right; a short distance from the mosque, graffiti scrawled on a wall read "Islam Out".
Mohammad Irfan, who represents a Muslim community group in the nearby town of Megara, said appearance was not everything.
"It looks nothing like a mosque .. But what is important is that there is a place for us to pray," he told Reuters.