As ancient Rome’s main port, Ostia welcomed grain, wine, livestock and olive oil from North Africa and Southern Italy to feed one million Romans. Yet despite an archaeological site spanning more than 150 football fields, Ostia attracts one-ninth as many visitors as Pompeii, and few signs help tourists find the train from Rome to Ostia. Once there, visitors must find the ruins virtually by intuition. But change may be afoot.

In coming months, projects in Ostia Antica (ancient Ostia) will reconstruct an unearthed ship, excavate...