diff --git a/.github/workflows/build_and_run_unit_tests_linux.yml b/.github/workflows/build_and_run_unit_tests_linux.yml
index 2aab9f98..b0a655f4 100644
--- a/.github/workflows/build_and_run_unit_tests_linux.yml
+++ b/.github/workflows/build_and_run_unit_tests_linux.yml
@@ -18,13 +18,13 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: 9.x
+          dotnet-version: 10.x
       - name: Restore dependencies
         run: dotnet restore
         working-directory: ./csharp
       - name: Build solution
         run: dotnet build --no-restore
         working-directory: ./csharp
-      - name: Test solution targeting dotnet9.0 only
-        run: dotnet test --no-build --verbosity normal -p:TargetFrameworks=net9.0
+      - name: Test solution targeting dotnet10.0 only
+        run: dotnet test --no-build --verbosity normal -p:TargetFrameworks=net10.0
         working-directory: ./csharp
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index ac33ca29..2c868ec1 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -46,7 +46,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: 9.x
+          dotnet-version: 10.x
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4
         with:
diff --git a/.github/workflows/run_all_tests_and_upload_code_coverage.yml b/.github/workflows/run_all_tests_and_upload_code_coverage.yml
index d91839d3..df2bb292 100644
--- a/.github/workflows/run_all_tests_and_upload_code_coverage.yml
+++ b/.github/workflows/run_all_tests_and_upload_code_coverage.yml
@@ -19,7 +19,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: 9.x
+          dotnet-version: 10.x
       - name: Run tests
         run: dotnet test csharp/PhoneNumbers.sln --configuration Release --verbosity normal --collect:"XPlat Code Coverage" --results-directory ./coverage
       - name: Upload coverage reports to Codecov
diff --git a/.github/workflows/run_performance_tests_windows.yml b/.github/workflows/run_performance_tests_windows.yml
index 89374515..11f1e562 100644
--- a/.github/workflows/run_performance_tests_windows.yml
+++ b/.github/workflows/run_performance_tests_windows.yml
@@ -28,15 +28,15 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
-          dotnet-version: 9.x
+          dotnet-version: 10.x
 
       - name: Run benchmarks (PR branch)
-        run: dotnet run -c Release --framework net9.0 -- --filter "*"
+        run: dotnet run -c Release --framework net10.0 -- --filter "*"
         working-directory: ./branch-code/csharp/PhoneNumbers.PerformanceTest
 
       - name: Run benchmarks (main branch)
         if: github.event_name == 'pull_request'
-        run: dotnet run -c Release --framework net9.0 -- --filter "*"
+        run: dotnet run -c Release --framework net10.0 -- --filter "*"
         working-directory: ./main-code/csharp/PhoneNumbers.PerformanceTest
 
       - name: Stage benchmark artifact
diff --git a/appveyor.yml b/appveyor.yml
index e88493b1..0507bc5f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -22,6 +22,11 @@ pull_requests:
 branches:
   only:
     - main
+install:
+  - ps: |
+      $ProgressPreference = 'SilentlyContinue'
+      Invoke-WebRequest -Uri 'https://dot.net/v1/dotnet-install.ps1' -OutFile "$env:TEMP\dotnet-install.ps1"
+      & "$env:TEMP\dotnet-install.ps1" -Channel 10.0 -InstallDir 'C:\Program Files\dotnet'
 before_build:
   - dotnet restore csharp -s https://api.nuget.org/v3/index.json
 build_script:
diff --git a/csharp/PhoneNumbers.Extensions.Test/PhoneNumbers.Extensions.Test.csproj b/csharp/PhoneNumbers.Extensions.Test/PhoneNumbers.Extensions.Test.csproj
index 0300c731..002de7d9 100644
--- a/csharp/PhoneNumbers.Extensions.Test/PhoneNumbers.Extensions.Test.csproj
+++ b/csharp/PhoneNumbers.Extensions.Test/PhoneNumbers.Extensions.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>netframework4.8;net8.0;net9.0</TargetFrameworks>
+        <TargetFrameworks>netframework4.8;net8.0;net9.0;net10.0</TargetFrameworks>
         <NoWarn>$(NoWarn);1591;CA1014;CA1062;CA1707;CA1812;CA1852</NoWarn>
         <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
         <EnableNETAnalyzers>true</EnableNETAnalyzers>
@@ -10,7 +10,7 @@
         <IsPackable>false</IsPackable>
     </PropertyGroup>
 
-    <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0'">
+    <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0' Or '$(TargetFramework)' == 'net10.0'">
       <Nullable>enable</Nullable>
     </PropertyGroup>
 
diff --git a/csharp/PhoneNumbers.Extensions/PhoneNumbers.Extensions.csproj b/csharp/PhoneNumbers.Extensions/PhoneNumbers.Extensions.csproj
index dd6db36d..b587e1d2 100644
--- a/csharp/PhoneNumbers.Extensions/PhoneNumbers.Extensions.csproj
+++ b/csharp/PhoneNumbers.Extensions/PhoneNumbers.Extensions.csproj
@@ -7,7 +7,7 @@
         <PackageId>libphonenumber-csharp.extensions</PackageId>
         <VersionPrefix>$(APPVEYOR_BUILD_VERSION)</VersionPrefix>
         <Authors>Thomas Clegg</Authors>
-        <TargetFrameworks>netstandard2.0;net8.0;net9.0</TargetFrameworks>
+        <TargetFrameworks>netstandard2.0;net8.0;net9.0;net10.0</TargetFrameworks>
         <LangVersion>preview</LangVersion>
         <PackageTags>phonenumber phone libphonenumber e164 e.164 international extensions</PackageTags>
         <PackageProjectUrl>https://github.com/twcclegg/libphonenumber-csharp</PackageProjectUrl>
diff --git a/csharp/PhoneNumbers.MetadataBuilder/PhoneNumbers.MetadataBuilder.csproj b/csharp/PhoneNumbers.MetadataBuilder/PhoneNumbers.MetadataBuilder.csproj
index f1a01515..7f4af41a 100644
--- a/csharp/PhoneNumbers.MetadataBuilder/PhoneNumbers.MetadataBuilder.csproj
+++ b/csharp/PhoneNumbers.MetadataBuilder/PhoneNumbers.MetadataBuilder.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net9.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <LangVersion>preview</LangVersion>
     <RootNamespace>PhoneNumbers.MetadataBuilder</RootNamespace>
diff --git a/csharp/PhoneNumbers.PerformanceTest/PhoneNumbers.PerformanceTest.csproj b/csharp/PhoneNumbers.PerformanceTest/PhoneNumbers.PerformanceTest.csproj
index c3af86af..a34eea02 100644
--- a/csharp/PhoneNumbers.PerformanceTest/PhoneNumbers.PerformanceTest.csproj
+++ b/csharp/PhoneNumbers.PerformanceTest/PhoneNumbers.PerformanceTest.csproj
@@ -2,11 +2,11 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>netframework4.8;net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>netframework4.8;net8.0;net9.0;net10.0</TargetFrameworks>
     <ImplicitUsings>disable</ImplicitUsings>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0' Or '$(TargetFramework)' == 'net10.0'">
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
diff --git a/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj b/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
index d2f95b74..532b9118 100644
--- a/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
+++ b/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netframework4.8;net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>netframework4.8;net8.0;net9.0;net10.0</TargetFrameworks>
     <!--
       Pin the C# language version so all TFMs (including netframework4.8, which the SDK
       otherwise defaults to C# 7.3) accept post-7.3 syntax used by tests: `using var`
@@ -14,7 +14,7 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0' Or '$(TargetFramework)' == 'net10.0'">
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
@@ -66,7 +66,7 @@
     <TestResourcesGeocodingDir>$(MSBuildThisFileDirectory)..\..\resources/test/geocoding</TestResourcesGeocodingDir>
     <TestResourcesCarrierDir>$(MSBuildThisFileDirectory)..\..\resources/test/carrier</TestResourcesCarrierDir>
     <MetadataBuilderProject>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\PhoneNumbers.MetadataBuilder.csproj</MetadataBuilderProject>
-    <MetadataBuilderDll>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\bin\$(Configuration)\net9.0\PhoneNumbers.MetadataBuilder.dll</MetadataBuilderDll>
+    <MetadataBuilderDll>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\bin\$(Configuration)\net10.0\PhoneNumbers.MetadataBuilder.dll</MetadataBuilderDll>
   </PropertyGroup>
 
   <!--
diff --git a/csharp/PhoneNumbers/PhoneNumbers.csproj b/csharp/PhoneNumbers/PhoneNumbers.csproj
index eeae05b0..632cdb11 100644
--- a/csharp/PhoneNumbers/PhoneNumbers.csproj
+++ b/csharp/PhoneNumbers/PhoneNumbers.csproj
@@ -7,7 +7,7 @@
     <PackageId>libphonenumber-csharp</PackageId>
     <VersionPrefix>$(APPVEYOR_BUILD_VERSION)</VersionPrefix>
     <Authors>Patrick Mézard;Thomas Clegg;Jarrod Alexander;Google;libphonenumber contributors</Authors>
-    <TargetFrameworks>netstandard2.0;net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;net8.0;net9.0;net10.0</TargetFrameworks>
     <LangVersion>preview</LangVersion>
     <PackageTags>phonenumber phone libphonenumber e164 e.164 international</PackageTags>
     <PackageProjectUrl>https://github.com/twcclegg/libphonenumber-csharp</PackageProjectUrl>
@@ -25,7 +25,7 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net8.0' Or '$(TargetFramework)' == 'net9.0' Or '$(TargetFramework)' == 'net10.0'">
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
@@ -70,7 +70,7 @@
     <BinaryCarrierDir>$(BaseIntermediateOutputPath)carrier</BinaryCarrierDir>
     <ResourcesDir>$(MSBuildThisFileDirectory)..\..\resources/</ResourcesDir>
     <MetadataBuilderProject>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\PhoneNumbers.MetadataBuilder.csproj</MetadataBuilderProject>
-    <MetadataBuilderDll>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\bin\$(Configuration)\net9.0\PhoneNumbers.MetadataBuilder.dll</MetadataBuilderDll>
+    <MetadataBuilderDll>$(MSBuildThisFileDirectory)..\PhoneNumbers.MetadataBuilder\bin\$(Configuration)\net10.0\PhoneNumbers.MetadataBuilder.dll</MetadataBuilderDll>
   </PropertyGroup>
 
   <!--