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Portsmouth

$488+ 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 7/26. Fares are subject to change and may not be available on all flights or dates of travel.
LAX — LHR
Feb 28 — Mar 71
Sat 2/28
Sat 3/7
1 adult, Economy
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Cheap 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 January 29, 2026.

This KLM deal was found by Cheapflights users on 1/26. 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 4/54:45 pm
LAX
-
SOU
1 stop16h 05m
KLM
Wed 4/299:05 am
SOU
-
LAX
1 stop34h 45m
KLM
Deal found 1/26$767
This Delta deal was found by Cheapflights users on 1/27. 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.
Sun 4/261:50 pm
LAX
-
SOU
1 stop34h 45m
Delta
Wed 5/209:05 am
SOU
-
LAX
1 stop13h 40m
Delta
Deal found 1/27$770
This Delta deal was found by Cheapflights users on 1/26. 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.
Sun 4/59:45 am
LAX
-
SOU
2 stops23h 05m
Delta
Wed 4/299:05 am
SOU
-
LAX
1 stop13h 40m
Delta
Deal found 1/26$772
This Delta deal was found by Cheapflights users on 1/27. 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.
Mon 4/279:45 am
LAX
-
SOU
2 stops23h 05m
Delta
Fri 5/159:05 am
SOU
-
LAX
1 stop13h 40m
Delta
Deal found 1/27$775
This Delta deal was found by Cheapflights users on 1/27. 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.
Mon 4/611:59 pm
LAX
-
SOU
2 stops32h 51m
Delta
Mon 4/275:20 pm
SOU
-
LAX
1 stop26h 30m
Delta
Deal found 1/27$787
This Delta deal was found by Cheapflights users on 1/27. 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.
Mon 8/174:45 pm
LAX
-
SOU
1 stop32h 00m
Delta
Mon 9/79:05 am
SOU
-
LAX
1 stop34h 45m
Delta
Deal found 1/27$819
This Delta deal was found by Cheapflights users on 1/27. 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 4/301:50 pm
LAX
-
SOU
1 stop19h 00m
Delta
Thu 5/149:05 am
SOU
-
LAX
1 stop13h 40m
Delta
Deal found 1/27$820
This Delta deal was found by Cheapflights users on 1/27. 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.
Sun 8/167:45 am
LAX
-
SOU
2 stops17h 00m
Delta
Tue 9/19:05 am
SOU
-
LAX
1 stop13h 40m
Delta
Deal found 1/27$824
This Delta deal was found by Cheapflights users on 1/27. 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.
Sun 4/57:35 am
LAX
-
SOU
2 stops25h 15m
Delta
Sun 4/265:20 pm
SOU
-
LAX
1 stop26h 30m
Delta
Deal found 1/27$825
This KLM deal was found by Cheapflights users on 1/27. 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.
Mon 8/101:50 pm
LAX
-
SOU
1 stop34h 55m
KLM
Wed 8/269:15 am
SOU
-
LAX
2 stops19h 48m
KLM
Deal found 1/27$829

Find flight deals from Riverside to Portsmouth

Keep the following information in mind while searching for Riverside to Portsmouth flight deals. Data was last updated January 29, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$767
(KLM)

One-way from

$488
(Delta)

Popular in

July

Cheapest in

April

Average price

$738
Provider with most accurate pricing for Los Angeles-London (LON) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Los Angeles-London (LON) flights.
Search Deals
From Riverside to Portsmouth
Search Deals
One-way flight from Riverside to Portsmouth
Search Deals
Highest demand for flights based on searches. 17% potential increase in price ($232 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($43 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2026
Search Deals

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 January 29, 2026.
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

Sun 4/5

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Wed 4/29

9:05 am-11:50 am

1 stop34h 45m

$767

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Mon 4/27

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Wed 5/20

9:05 am-2:45 pm

1 stop13h 40m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Mon 4/27

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Fri 5/15

9:05 am-2:45 pm

1 stop13h 40m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Tue 4/28

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Wed 5/20

9:05 am-2:45 pm

1 stop13h 40m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Sun 4/26

1:50 pm-8:35 am

1 stop34h 45m

Southampton Eastleigh

Tue 5/19

9:05 am-11:50 am

1 stop34h 45m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Wed 4/29

1:50 pm-8:35 am

1 stop34h 45m

Southampton Eastleigh

Tue 5/19

5:20 pm-11:50 am

1 stop26h 30m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Tue 4/28

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Fri 5/15

9:05 am-2:45 pm

1 stop13h 40m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Tue 3/31

4:45 pm-4:50 pm

1 stop16h 05m

Southampton Eastleigh

Mon 4/27

5:20 pm-2:45 pm

1 stop29h 25m

$770

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Sun 4/26

11:59 pm-8:35 am

2 stops24h 36m

Southampton Eastleigh

Thu 5/14

5:20 pm-2:45 pm

1 stop29h 25m

$775

Los AngelesSouthampton

LAX - SOU

LAXSOU

Los Angeles

Mon 4/27

10:55 pm-8:35 am

2 stops25h 40m

Southampton Eastleigh

Tue 5/19

5:20 pm-11:50 am

1 stop26h 30m

$775

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/28

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 $222). Flying from Riverside to Portsmouth in June is currently the most expensive (average of $569). 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 January 29, 2026.

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 afternoon, which can drop the price by up to 33% versus a flight in the morning.

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 January 24, 2026.

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

Weekly flight availability from Riverside to Portsmouth

Explore weekly flight availability from Riverside to Portsmouth. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated January 29, 2026.

The most flights from R1V to P0R are scheduled on a Thursday (51 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (27 on average).

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 January 29, 2026.
Peruse reviews from past customers who have flown with Delta, KLM, and Aer Lingus 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
8,128 reviews

Boarding

8.1

Food

7.2

Overall

7.9

Crew

8.5

Entertainment

7.8

Comfort

7.9

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
8,128 reviews
Delta
7.9
Good
8,128 reviews

Boarding

8.1

Food

7.2

Overall

7.9

Crew

8.5

Entertainment

7.8

Comfort

7.9

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
1,443 reviews
Delta
7.9
Good
8,128 reviews

Boarding

8.1

Food

7.2

Overall

7.9

Crew

8.5

Entertainment

7.8

Comfort

7.9

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
1,443 reviews
Delta
7.9
Good
8,128 reviews

Boarding

8.1

Food

7.2

Overall

7.9

Crew

8.5

Entertainment

7.8

Comfort

7.9

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?

    KLM and Delta can get you from Riverside to Portsmouth in just under 16h 05m. 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: Air Canada (93%), Austrian Airlines (93%), United Airlines (93%).

  • What are the cheapest flights from Riverside to Portsmouth?

    On average you can expect to pay $3,136 for a flight from Riverside to Portsmouth. The cheapest flight overall is $254 while the most popular route, (Los Angeles - Southampton Eastleigh) is currently priced at $767.

  • 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 $222). Flying from Riverside to Portsmouth in June is currently the most expensive (average of $569). 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 January 29, 2026.
AirlineCheapestAverageFlexibilityOn-time
JetBlueCheapest$273Average$806FlexibilityNo cancel feeOn-time62%
SWISSCheapest$336Average$900FlexibilityNo cancel feeOn-time79%
Norse Atlantic UKCheapest$352Average$680FlexibilityNo cancel feeOn-timeN/A
TAP AIR PORTUGALCheapest$375Average$571FlexibilityNo cancel feeOn-timeN/A
Scandinavian AirlinesCheapest$468Average$621FlexibilityNo cancel feeOn-time77%
Aer LingusCheapest$476Average$880FlexibilityNo cancel feeOn-timeN/A
FinnairCheapest$485Average$690FlexibilityNo cancel feeOn-time76%
British AirwaysCheapest$498Average$802FlexibilityNo cancel feeOn-time70%
KLMCheapest$527Average$799FlexibilityNo cancel feeOn-time75%
DeltaCheapest$530Average$760FlexibilityNo cancel feeOn-timeN/A

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