According Exceltur, season could start 4 weeks after government ending (provably April 26) the big confinement, but they talk about national tourism, so ibiza will see delayed the arrival of foreign tourists.
So being positive I think the optimistic prediction is very late June, depends on the situation in the other countries and the restrictions of capacity in places like nightclubs that the Spanish government will announce once the confinement is finished. None government wants to make mistakes in that crisis so strong restrictions are expected regarding big amounts of people meetings.
The second option of starting season is mid July, and the worst option in my opinion is mid August.
For sure is more than possible that some clubs decides not to open this season, and others will only opens 3 nights friday, saturday, sunday (when the few tourists will decide to travel for 3-4 days escape).
One thing is clear, of the few tourism that is going to come to Ibiza this summer the majority will be families or completely different than clubbers tourism, because families or similars not focus their holidays to restrictions in closed spaces. (La Vanguardia yesterday predicts Balearic Islands will lose 40% of tourism),
"In Exceltur's most optimistic scenario, "from mid-June there will start to be some movement" and the level prior to the health crisis will not recover until October. All this, considering the projections of organizations such as the Polytechnic University of Valencia that points to the peak of infections and deaths will be reached in Spain around May 20. From then on, he considers that "it will probably be a few weeks (between three and four) until the travel decisions begin to recover," with a slow and gradual return to normality. "
In addition, demand is expected to undergo a recovery at two speeds: a faster one for local trips and private vehicles, basically national demand, and elements of the tourist offer of limited size; and a slower one in trips with shared transport (train or plane, fundamentally" https://www.eleconomista.es/empresa...rano-y-reclama-al-Gobierno-ayudas-reales.html