France's entrance into the war offered bright prospects for the Americans. The flow of weapons and supplies intensified. The British effort in America diminished as men, ships, and resources were diverted elsewhere. There would be no more armies and armadas like those that had gathered outside New York in 1776. The arrival of French fleets and armies might help the Americans pry the British from their bases along the coast.

Admiral d'Estaing appeared in American waters with a fleet of twelve ships of the line and four frigates on July 8. Aboard his ships were 4,000 soldiers with which Washington hoped to drive the British out of New York City. D'Estaing outnumbered and outgunned Admiral Richard Howe's ships anchored off Sandy Hook. He wanted to attack the British, but to get at them he had to get his heavy ships over a sandbar that ran from Staten Island to Sandy Hook. This proved impossible. After eleven days, d'Estaing gave up.

The futile operation had eaten into the time that d'Estaing could spend assisting the Americans. He was under orders to proceed to the West Indies to protect French possessions there from possible British attacks. Washington and d'Estaing worked out a new plan to overwhelm the British garrison at Newport, Rhode Island. D'Estaing's naval and land forces would cooperate with an army commanded by John Sullivan.

The British maintained a force of 3,000 men in Newport, commanded by Sir Robert Pigot. Newport lay at the southern tip of an island, separated from the mainland by a channel that could be traversed by a ferry. In anticipation of d'Estaing's arrival, Sullivan had been posted to Providence with 1,000 Continentals. He called on the New England states for reinforcements and collected a force of 6,000 militia commanded by John Hancock. Washington sent Lafayette and Greene with veteran troops from his army.

The allied plan called for d'Estaing to land his infantry on the western part of the island, to be joined by Sullivan crossing over from the east. D'Estaing's fleet arrived on July 29. The British were forced to burn or sink a number of frigates and smaller vessels at Newport to keep them out of the hands of the French. Land operations were set to begin on August 9. Fearing that the British would garrison some fortifications near his landing point, Sullivan acted a day early. Admiral d'Estaing took this as a slight, opening a rift between the allied commanders that would eventually widen into a full breach.

Admiral Howe appeared outside the town on August 9 with a reinforced fleet of twenty ships. D'Estaing halted the landing of his troops, recalling them to their ships. The next day he took advantage of a favorable wind to bear down on the British fleet. Howe would not fight at a disadvantage and commenced what became two days of maneuvering for the rival fleets. This naval pirouette was broken up by a massive storm that scattered and heavily damaged both fleets. The British fell back to New York to refit. Despite the protests of Sullivan and Lafayette, d'Estaing took his fleet to Boston for repairs. From there he sailed to the West Indies.

When the French fleet departed, Sullivan's militia deserted. With the military tables turned, Sullivan was forced to make a fighting retreat. Sullivan got away a day before the British received substantial reinforcements. Both sides suffered around 300 casualties. The frustrated American general publicly vented his anger at what he believed was desertion by the French. D'Estaing responded with heat. It took skillful diplomacy by Washington and a timely resolution of thanks by Congress to restore allied harmony.