Popular holiday resorts Agadir, Marrakesh and Essaouira were to be attacked along with foreign cruise liners visiting Casablanca.
The plot was uncovered following an incident on 11 March when Abdelfettah Raydi, 23, blew himself up in an internet caf in Casablanca, injuring four customers. The explosion happened during a scuffle when Raydi was challenged for looking at jihad websites.
A follow-up investigation led to the arrest of 24 other fundamentalists.
Chakib Benmoussa, Morocco's interior minister, revealed details of the plot and said that at least half of those arrested had intended to blow themselves up in a series of suicide attacks on tourist targets.
Police are still searching for six other alleged members of the cell.
Morocco has been on red alert since the beginning of last month. This follows a surge in activities across Arab north-west Africa by the self-styled Salafist Group for Preaching and Combat, which recently changed its name to al-Qaeda of the Islamic Magreb with the personal blessing of Osama bin Laden.
Last night, a Foreign Office spokeswoman said the advice on its website - updated after the suicide bombing in Casablanca - was that there was a "high threat from terrorism" in Morocco.