Here's a suggestive itinerary for a holiday from the UK with 3 nights in Hanoi, followed by 3 nights in Hoi An, and ending with 3 nights in Ho Chi Minh City:

Day 1: Arrival in Hanoi

• Fly from the UK to Hanoi, the capital city of Vietnam.
• Arrive in Hanoi and transfer to your hotel.
• Spend the afternoon exploring the charming Old Quarter, with its narrow streets, bustling markets, and vibrant atmosphere.
• Visit Hoan Kiem Lake and Ngoc Son Temple.
• Enjoy a traditional Vietnamese dinner at a local restaurant.

Day 2: Hanoi City Exploration

• Start the day with a visit to the Ho Chi Minh Mausoleum, where you can pay respects to Vietnam's iconic leader.
• Explore the nearby Presidential Palace and the One Pillar Pagoda.
• Visit the Temple of Literature, Vietnam's first university.
• Enjoy a cyclo ride (a type of bicycle rickshaw) through the streets of Hanoi's Old Quarter.
• In the evening, experience the lively street food scene in Hanoi and savor local delicacies.

Day 3: Hanoi Sightseeing

• Take a day trip to the nearby Ninh Binh province and explore the breathtaking landscapes of Tam Coc, often referred to as "Halong Bay on land."
• Enjoy a scenic boat ride through the karst limestone formations and visit ancient temples.
• Return to Hanoi in the evening and enjoy dinner at a local restaurant.

Day 4: Transfer to Hoi An

• Travel from Hanoi to Hoi An, either by a domestic flight or an overnight train.
• Arrive in Hoi An and check into your hotel.
• Spend the afternoon exploring the UNESCO World Heritage-listed Ancient Town of Hoi An, known for its well-preserved architecture, lantern-lit streets, and vibrant markets.
• Visit the Japanese Covered Bridge, the Assembly Hall of the Fujian Chinese Congregation, and the Hoi An Museum of History and Culture.
• Enjoy a relaxing boat ride along the Thu Bon River, taking in the scenic views.

Day 5: Hoi An and Surroundings

• Embark on a cycling tour of the surrounding countryside, visiting traditional villages, rice fields, and local handicraft workshops.
• Take a cooking class and learn to prepare traditional Vietnamese dishes.
• Relax on An Bang Beach or Cua Dai Beach and soak up the sun.
• In the evening, enjoy the magical atmosphere of Hoi An's lantern-lit streets and dine at a riverside restaurant.

Day 6: Transfer to Ho Chi Minh City

• Travel from Hoi An to Ho Chi Minh City by a domestic flight.
• Arrive in Ho Chi Minh City and check into your hotel.
• Spend the afternoon exploring the city's landmarks, such as the Reunification Palace, the Notre-Dame Cathedral, and the Central Post Office.
• Visit the War Remnants Museum to learn about Vietnam's history.
• Enjoy a dinner cruise along the Saigon River.

Day 7: Ho Chi Minh City and Cu Chi Tunnels

• Take a day trip to the Cu Chi Tunnels, an intricate network of underground tunnels used during the Vietnam War.
• Explore the tunnels and learn about their significance in Vietnam's history.
• Return to Ho Chi Minh City in the afternoon and visit the bustling Ben Thanh Market for some souvenir shopping.
• In the evening, explore the vibrant nightlife of Ho Chi Minh City.

Day 8: Mekong Delta Excursion

• Embark on a full-day excursion to the Mekong Delta, a vast network of rivers and canals.
• Cruise along the Mekong River, visit local villages, and experience the agricultural activities of the region.
• Taste tropical fruits, sample local delicacies, and learn about the rural way of life.
• Return to Ho Chi Minh City in the evening.

Day 9: Departure

• On your last day, enjoy some free time for shopping or exploring more of Ho Chi Minh City.
• Transfer to the airport for your return flight to the UK, carrying with you unforgettable memories of Vietnam.

This itinerary provides a balanced mix of cultural experiences, historical landmarks, natural beauty, and culinary delights in Hanoi, Hoi An, and Ho Chi Minh City. Feel free to adjust the itinerary based on your preferences and the specific attractions you wish to visit.