The Moroccan court in Nador, near the North African kingdom's border with Melilla, sentenced "all the (33) migrants to 11 months behind bars each", attorney Khalid Ameza told AFP, describing the ruling as "a very heavy sentence".
At least 23 migrants died after around 2,000 people, many from Sudan, stormed the frontier on June 24 -- the worst death toll in years of attempted migrant crossings into Spain's Ceuta and Melilla enclaves, which represent the EU's only land borders with Africa.
The 33 irregular migrants were prosecuted for "illegal entry onto Moroccan soil", "violence against law enforcement officers", participating in an "armed gathering" and "refusing to obey orders", according to a court statement.
"We hope that the appeals court will rectify this severe sentence," the AMDH human rights group's Nador office said.
A separate trial, also in Nador, of a group of 29 irregular migrants including a minor opened last week but has been adjourned to July 27, the court said.
That group is accused of "participating in a criminal gang with a view to organising and facilitating" irregular migration, among other charges.
Spanish rights group Caminando Fronteras says as many as 37 people lost their lives in the June 24 incident.
The United Nations, the African Union and independent rights groups have condemned the use of excessive force by Moroccan and Spanish security personnel.
Morocco's state-backed CNDH rights group said last week that those who died likely "suffocated".
The CNDH defended Moroccan forces' actions, saying cases of violence were "isolated" and citing the danger posed by "the large number of migrants" carrying sticks and stones.