Parachute drops, ceremonies and fireworks are planned to commemorate the Normandy landings that launched the beginning of the end of World War II.
On Saturday Prince Charles and Gordon Brown will attend a ceremony alongside the French and US presidents.
It was on the evening of 5 June 1944 that a force of 130,000 allied troops set off for France from England.
Their arrival on the French coast will be replicated early on Friday morning by a landing craft from 1 Assault Group Royal Marines in Port au Bessin.
Remembrance services
There will be a mass drop of British parachutists at the Pegasus Memorial in Ranville at 0745 BST.
The Allied glider landings and parachute drops in the early hours of 6 June 1944 enabled British troops to take the strategically important Pegasus Bridge near Caen.
The Normandy Veterans Association, for whom the occasion marks the last visit to France as a group, will be attending a service and parade at Monty's statue in Colleville-Montgomery at 1000 BST.
At 1300 BST the Royal British Legion, schoolchildren and veterans will lay a wreath at Bayeux International War Cemetery.
Later around 20 pipers will play as veteran Bill Millin visits the museum at Pegasus Bridge. On D-Day Mr Millin played his brigade ashore with his bagpipes.
In Asnelles around 80 children from London and the south east will plant flags in the beach with messages of thanks and talk to veterans about their experiences.
Late on Friday evening there will be 25 simultaneous firework displays along the Normandy coastline followed by the illumination of Port Winston, a temporary harbour built by the British in Arromanches.
The day will end with a midnight vigil attended by Chief of General Staff General Sir Richard Dannatt at Pegasus Bridge, Ranville.
The main commemorations will take place on Saturday.
On Tuesday, Clarence House confirmed that Prince Charles would travel to Normandy after he received a last-minute invitation from the French government.
French officials denied they had intended to snub the Royal Family after it emerged that the Queen had not been invited to the commemorations.
The prince is expected to attend at least one event alongside US President Barack Obama, French President Nicolas Sarkozy and Gordon Brown.
They will gather at the Normandy American Cemetery, by Omaha Beach - code name for one of the five beaches where the Allied invasion of German-occupied France began.
Hundreds of British veterans will hold their main memorial event at the Arromanches beaches where thousands of UK and Canadian troops came ashore on 6 June 1944, and during the following days.
There will also be a Royal British Legion Service of Remembrance at Bayeux Cathedral.
