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Portsmouth

$489+ Cheap flights from Riverside, CA to Portsmouth, England

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 1/19. Fares are subject to change and may not be available on all flights or dates of travel.
LAX — LHR
Nov 29 — Dec 61
Sat 11/29
Sat 12/6
1 adult, Economy
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Cheap flight deals from Riverside to Portsmouth

Keep the following information in mind while searching for Riverside to Portsmouth flight deals. Data was last updated October 30, 2025.

Most accurate provider

Gotogate
3 stars

Most trusted provider

Gotogate
3 stars

Round-trip from

$741
(Delta)

One-way from

$489
(Delta)

Popular in

January

Cheapest in

April

Average price

$1,108
Provider with most accurate pricing for Los Angeles-London (LON) flight deals.
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Provider most trusted by Cheapflights users for Los Angeles-London (LON) flights.
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From Riverside to Portsmouth
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One-way flight from Riverside to Portsmouth
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Highest demand for flights based on searches. 19% potential increase in price ($291 potential increase over avg. RT price).
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Cheapest flight prices on average. 9% potential price decrease ($101 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find flight deals from Riverside to Portsmouth

Cheapest flights from Riverside to Portsmouth
Explore the most affordable flight options available from Riverside to Portsmouth. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 30, 2025.

This Delta deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/271:45 pmLAX - SOU
1 stop19h 15mDelta
Sat 12/65:30 pmSOU - LAX
1 stop26h 15mDelta
Deal found 10/30$741
This Delta deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/2711:55 amLAX - SOU
2 stops21h 05mDelta
Sun 12/79:30 amSOU - LAX
1 stop34h 15mDelta
Deal found 10/30$745
This Delta deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/271:45 pmLAX - SOU
1 stop19h 15mDelta
Mon 12/86:05 pmSOU - LAX
2 stops29h 55mDelta
Deal found 10/30$751
This Delta deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/261:45 pmLAX - SOU
1 stop19h 40mDelta
Thu 12/46:05 pmSOU - LAX
1 stop25h 40mDelta
Deal found 10/30$790
This Delta deal was found by Cheapflights users on 10/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/21:45 pmLAX - SOU
1 stop19h 15mDelta
Wed 12/245:30 pmSOU - LAX
2 stops31h 05mDelta
Deal found 10/29$800
This Delta deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/251:45 pmLAX - SOU
1 stop19h 15mDelta
Fri 12/55:30 pmSOU - LAX
1 stop26h 15mDelta
Deal found 10/30$840
This KLM deal was found by Cheapflights users on 10/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/71:45 pmLAX - SOU
1 stop19h 40mKLM
Sun 12/146:05 pmSOU - LAX
1 stop25h 40mKLM
Deal found 10/29$842
This KAYAK deal was found by Cheapflights users on 10/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/298:15 pmLAX - SOU
1 stop35h 20mAer Lingus
Sun 12/79:30 amSOU - LAX
1 stop17h 00mAer Lingus
Deal found 10/29$1,050
This KAYAK deal was found by Cheapflights users on 10/30. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/53:55 pmLAX - SOU
1 stop19h 45mAer Lingus
Tue 11/118:10 pmSOU - LAX
1 stop30h 20mAer Lingus
Deal found 10/30$1,068

Cheapflights Fare Finder

 
Customize your flight search to find flights from Riverside to Portsmouth that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated October 30, 2025.
Use the filters below to find and compare flights from Riverside to Portsmouth that are best for you.

Fly from

Riverside

Fly to

Portsmouth

Route

Depart

Return

Price

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Fri 11/28

1:40 pm-5:00 pm

1 stop19h 20m

Southampton Eastleigh

Wed 12/3

8:40 am-11:45 am

1 stop35h 05m

$741

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Fri 11/28

1:40 pm-5:00 pm

1 stop19h 20m

Southampton Eastleigh

Tue 12/2

5:30 pm-11:45 am

1 stop26h 15m

$741

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Sun 11/30

1:45 pm-5:25 pm

1 stop19h 40m

Southampton Eastleigh

Sun 12/7

6:05 pm-11:45 am

1 stop25h 40m

$741

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Sat 11/29

1:45 pm-8:10 am

1 stop34h 25m

Southampton Eastleigh

Mon 12/8

6:05 pm-11:45 am

1 stop25h 40m

$741

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Fri 11/28

8:36 am-8:50 am

2 stops16h 14m

Southampton Eastleigh

Sat 12/6

9:25 am-11:45 am

1 stop34h 20m

$745

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Thu 11/27

11:55 am-5:00 pm

2 stops21h 05m

Southampton Eastleigh

Sun 12/7

9:30 am-11:45 am

1 stop34h 15m

$745

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Thu 11/27

7:15 am-8:05 am

2 stops16h 50m

Southampton Eastleigh

Thu 12/4

6:05 pm-11:45 am

1 stop25h 40m

$745

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Thu 11/27

5:45 am-5:00 pm

2 stops27h 15m

Southampton Eastleigh

Sat 12/6

9:25 am-11:45 am

1 stop34h 20m

$745

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Thu 11/27

2:00 pm-5:00 pm

2 stops19h 00m

Southampton Eastleigh

Fri 12/5

8:40 am-11:45 am

1 stop35h 05m

$745

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Thu 11/27

1:45 pm-5:00 pm

1 stop19h 15m

Southampton Eastleigh

Mon 12/8

6:05 pm-4:00 pm

2 stops29h 55m

$751

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/28

Showing 1-10 of 20 results
1
2

Best time to book a flight from Riverside to Portsmouth

Have a flexible travel schedule? Discover the best time to fly to Portsmouth from Riverside with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Riverside to Portsmouth

What is the cheapest month to book a flight from Riverside to Portsmouth?

Currently, October is the cheapest month in which you can book a flight from Riverside to Portsmouth (average of $251). Flying from Riverside to Portsmouth in June is currently the most expensive (average of $564). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from R1V to P0R?

Find hourly flight availability from Riverside to Portsmouth. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated October 30, 2025.

When flying from Riverside to Portsmouth, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 23% versus a flight at noon.

What is the cheapest day to fly from Riverside to Portsmouth?

Use this chart to determine the cheapest time to fly round-trip from Riverside to Portsmouth. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Riverside to Portsmouth flight should consider departing on Friday evenings when fares are most often at their lowest. Sunday evenings flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing Portsmouth

Get insights into the airlines that provide service to Portsmouth. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Portsmouth. Reviews last updated October 30, 2025.
Peruse reviews from past customers who have flown with Delta, KLM, and Virgin Atlantic from Riverside to Portsmouth to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
7,998 reviews

Comfort

7.9

Entertainment

7.9

Crew

8.5

Overall

7.9

Boarding

8.2

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Delta
7.9
Good
7,998 reviews
Delta
7.9
Good
7,998 reviews

Comfort

7.9

Entertainment

7.9

Crew

8.5

Overall

7.9

Boarding

8.2

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
KLM
7.7
Good
1,406 reviews
Delta
7.9
Good
7,998 reviews

Comfort

7.9

Entertainment

7.9

Crew

8.5

Overall

7.9

Boarding

8.2

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Virgin Atlantic
7.5
Good
671 reviews
Delta
7.9
Good
7,998 reviews

Comfort

7.9

Entertainment

7.9

Crew

8.5

Overall

7.9

Boarding

8.2

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.
Aer Lingus
7.2
Good
1,365 reviews
Delta
7.9
Good
7,998 reviews

Comfort

7.9

Entertainment

7.9

Crew

8.5

Overall

7.9

Boarding

8.2

Food

7.3

Reviews

1 / 20
10.0
Excellent

Aaron,Oct 2024

LAX - LHR

This was a flight operated by Virgin Atlantic in their Upper Class cabin. Overall, an outstanding experience.

Related info for your journey

Find useful and relevant information for your journey from Riverside to Portsmouth. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Riverside to Portsmouth?

    Delta can get you from Riverside to Portsmouth in just under 19h 20m. Your travel time can differ by up to . Airlines will cover a distance of 5434 mi.

  • What are the most reliable airlines from Riverside to Portsmouth?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Riverside to Portsmouth on time: KLM (95%), Air France (95%), Delta (95%).

  • What are the cheapest flights from Riverside to Portsmouth?

    On average you can expect to pay $3,109 for a flight from Riverside to Portsmouth. The cheapest flight overall is $329 while the most popular route, (Los Angeles - Southampton Eastleigh) is currently priced at $799.

  • Can I find deals for flights from Riverside to Portsmouth that include hotel bookings?

    Yes. In addition to deals on Riverside to Portsmouth flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Riverside to Portsmouth?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Riverside to Portsmouth.

  • Can I find deals for business class flights from Riverside to Portsmouth?

    Yes. Cheapflights offers flight deals from Riverside to Portsmouth by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Riverside to Portsmouth?

    Currently, October is the cheapest month in which you can book a flight from Riverside to Portsmouth (average of $251). Flying from Riverside to Portsmouth in June is currently the most expensive (average of $564). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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Top 10 airlines flying from Riverside to Portsmouth

Discover the top 10 airlines that operate flights from Riverside to Portsmouth. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated October 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
WestJetCheapest$272Average$1,046FlexibilityNo cancel feeOn-time60%
JetBlueCheapest$273Average$810FlexibilityNo cancel feeOn-time62%
SWISSCheapest$336Average$922FlexibilityNo cancel feeOn-time79%
Norse Atlantic UKCheapest$359Average$680FlexibilityNo cancel feeOn-timeN/A
LufthansaCheapest$397Average$893FlexibilityNo cancel feeOn-time76%
Scandinavian AirlinesCheapest$419Average$594FlexibilityNo cancel feeOn-time77%
TAP AIR PORTUGALCheapest$427Average$628FlexibilityNo cancel feeOn-timeN/A
Aer LingusCheapest$476Average$888FlexibilityNo cancel feeOn-timeN/A
FinnairCheapest$487Average$703FlexibilityNo cancel feeOn-time76%
British AirwaysCheapest$498Average$916FlexibilityNo cancel feeOn-time70%

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