diff --git a/CHANGELOG.md b/CHANGELOG.md
index 651ad6aea0..bde86c6d92 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - Use a default value of 60 seconds if a `Retry-After` header is not present. ([#1537](https://github.com/getsentry/sentry-dotnet/pull/1537))
 - Add new Protocol definitions for DebugImages and AddressMode ([#1513](https://github.com/getsentry/sentry-dotnet/pull/1513))
 - Add `HttpTransport` extensibility and synchronous serialization support ([#1560](https://github.com/getsentry/sentry-dotnet/pull/1560))
+- Add `UseAsyncFileIO` to Sentry options (enabled by default) ([#1564](https://github.com/getsentry/sentry-dotnet/pull/1564))
 
 ### Fixes
 
diff --git a/src/Sentry/FileAttachmentContent.cs b/src/Sentry/FileAttachmentContent.cs
index 2c9fba32bb..157ddc1a3d 100644
--- a/src/Sentry/FileAttachmentContent.cs
+++ b/src/Sentry/FileAttachmentContent.cs
@@ -8,11 +8,26 @@ namespace Sentry
     public class FileAttachmentContent : IAttachmentContent
     {
         private readonly string _filePath;
+        private readonly bool _readFileAsynchronously;
 
         /// <summary>
         /// Creates a new instance of <see cref="FileAttachmentContent"/>.
         /// </summary>
-        public FileAttachmentContent(string filePath) => _filePath = filePath;
+        /// <param name="filePath">The path to the file to attach.</param>
+        public FileAttachmentContent(string filePath) : this(filePath, true)
+        {
+        }
+
+        /// <summary>
+        /// Creates a new instance of <see cref="FileAttachmentContent"/>.
+        /// </summary>
+        /// <param name="filePath">The path to the file to attach.</param>
+        /// <param name="readFileAsynchronously">Whether to use async file I/O to read the file.</param>
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously)
+        {
+            _filePath = filePath;
+            _readFileAsynchronously = readFileAsynchronously;
+        }
 
         /// <inheritdoc />
         public Stream GetStream() => new FileStream(
@@ -21,6 +36,6 @@ public class FileAttachmentContent : IAttachmentContent
             FileAccess.Read,
             FileShare.ReadWrite,
             bufferSize: 4096,
-            useAsync: true);
+            useAsync: _readFileAsynchronously);
     }
 }
diff --git a/src/Sentry/ScopeExtensions.cs b/src/Sentry/ScopeExtensions.cs
index e99e4b0ce1..d49a15caee 100644
--- a/src/Sentry/ScopeExtensions.cs
+++ b/src/Sentry/ScopeExtensions.cs
@@ -159,7 +159,7 @@ public static void AddAttachment(
             scope.AddAttachment(
                 new Attachment(
                     type,
-                    new FileAttachmentContent(filePath),
+                    new FileAttachmentContent(filePath, scope.Options.UseAsyncFileIO),
                     Path.GetFileName(filePath),
                     contentType));
 
diff --git a/src/Sentry/SentryOptions.cs b/src/Sentry/SentryOptions.cs
index a6f4d63ef7..45144f2b67 100644
--- a/src/Sentry/SentryOptions.cs
+++ b/src/Sentry/SentryOptions.cs
@@ -564,6 +564,15 @@ public StackTraceMode StackTraceMode
         /// </remarks>
         public bool AutoSessionTracking { get; set; } = false;
 
+        /// <summary>
+        /// Whether the SDK should attempt to use asynchronous file I/O.
+        /// For example, when reading a file to use as an attachment.
+        /// </summary>
+        /// <remarks>
+        /// This option should rarely be disabled, but is necessary in some environments such as Unity WebGL.
+        /// </remarks>
+        public bool UseAsyncFileIO { get; set; } = true;
+
         /// <summary>
         /// Delegate which is used to check whether the application crashed during last run.
         /// </summary>
diff --git a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.Core3_1.verified.txt b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
index 59cc4444a1..93b767227c 100644
--- a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
+++ b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
index ecd4dca74a..76bfd2921e 100644
--- a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
+++ b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
index 2327269c45..1bb34f5450 100644
--- a/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
+++ b/test/Sentry.DiagnosticSource.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.Core2_1.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.Core2_1.verified.txt
index ea672dbffc..abe61dffc8 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.Core2_1.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.Core2_1.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.Core3_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.Core3_0.verified.txt
index d852d89787..5136f07aa9 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.Core3_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.Core3_0.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.Core3_1.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
index 59cc4444a1..93b767227c 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.Core3_1.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet4_6.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet4_6.verified.txt
index ee3364a321..5bb1bc77f1 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet4_6.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet4_6.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -496,6 +497,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
index ecd4dca74a..76bfd2921e 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet5_0.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
index 2327269c45..1bb34f5450 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet6_0.verified.txt
@@ -112,6 +112,7 @@ namespace Sentry
     public class FileAttachmentContent : Sentry.IAttachmentContent
     {
         public FileAttachmentContent(string filePath) { }
+        public FileAttachmentContent(string filePath, bool readFileAsynchronously) { }
         public System.IO.Stream GetStream() { }
     }
     public static class HasBreadcrumbsExtensions
@@ -497,6 +498,7 @@ namespace Sentry
         public Sentry.StackTraceMode StackTraceMode { get; set; }
         public double TracesSampleRate { get; set; }
         public System.Func<Sentry.TransactionSamplingContext, double?>? TracesSampler { get; set; }
+        public bool UseAsyncFileIO { get; set; }
     }
     public static class SentryOptionsExtensions
     {