HONG KONG—A 32-hour visit to the city by JPMorgan Chase & Co. Chief Executive Jamie Dimon has drawn attention to how shut-off the Chinese financial hub has become after two years of keeping coronavirus cases at bay.

Mr. Dimon’s visit—the first known trip to the city by the head of a Wall Street bank since the beginning of the pandemic—came just days after Hong Kong tightened its quarantine rules to remove previous exemptions for travelers including top international financial executives.