diff --git a/src/Sentry/Internal/Hub.cs b/src/Sentry/Internal/Hub.cs
index 67318abc54..9c61f62228 100644
--- a/src/Sentry/Internal/Hub.cs
+++ b/src/Sentry/Internal/Hub.cs
@@ -1,6 +1,7 @@
 using Sentry.Extensibility;
 using Sentry.Infrastructure;
 using Sentry.Integrations;
+using Sentry.Internal.Extensions;
 using Sentry.Protocol.Envelopes;
 using Sentry.Protocol.Metrics;
 
@@ -757,6 +758,28 @@ public SentryId CaptureCheckIn(
         return SentryId.Empty;
     }
 
+    // Internal capture method that allows the Unity SDK to send attachments after an already captured event.
+    // Kept internal as the preferred way of adding attachments is either on the scope or directly on the event.
+    // See https://develop.sentry.dev/sdk/data-model/envelope-items/#attachment
+    internal bool CaptureAttachment(SentryId eventId, SentryAttachment attachment)
+    {
+        if (!IsEnabled || eventId == SentryId.Empty || attachment.IsNull())
+        {
+            return false;
+        }
+
+        try
+        {
+            var envelope = Envelope.FromAttachment(eventId, attachment, _options.DiagnosticLogger);
+            return CaptureEnvelope(envelope);
+        }
+        catch (Exception e)
+        {
+            _options.LogError(e, "Failure to capture attachment");
+            return false;
+        }
+    }
+
     public async Task FlushAsync(TimeSpan timeout)
     {
         try
diff --git a/src/Sentry/Protocol/Envelopes/Envelope.cs b/src/Sentry/Protocol/Envelopes/Envelope.cs
index b62dc82c98..0c6dec0281 100644
--- a/src/Sentry/Protocol/Envelopes/Envelope.cs
+++ b/src/Sentry/Protocol/Envelopes/Envelope.cs
@@ -445,6 +445,12 @@ internal static Envelope FromClientReport(ClientReport clientReport)
         return new Envelope(header, items);
     }
 
+    /// <summary>
+    /// Creates an envelope that contains only an attachment for an existing event.
+    /// </summary>
+    internal static Envelope FromAttachment(SentryId eventId, SentryAttachment attachment, IDiagnosticLogger? logger = null) =>
+        new(eventId, CreateHeader(eventId), [EnvelopeItem.FromAttachment(attachment)]);
+
     private static async Task<IReadOnlyDictionary<string, object?>> DeserializeHeaderAsync(
         Stream stream,
         CancellationToken cancellationToken = default)
diff --git a/test/Sentry.Testing/NullAttachmentContent.cs b/test/Sentry.Testing/NullAttachmentContent.cs
new file mode 100644
index 0000000000..ea96a54e5c
--- /dev/null
+++ b/test/Sentry.Testing/NullAttachmentContent.cs
@@ -0,0 +1,10 @@
+namespace Sentry.Testing;
+
+internal sealed class NullAttachmentContent : IAttachmentContent
+{
+    public static NullAttachmentContent Instance { get; } = new();
+
+    public Stream GetStream() => Stream.Null;
+
+    private NullAttachmentContent() { }
+}
diff --git a/test/Sentry.Tests/HubTests.cs b/test/Sentry.Tests/HubTests.cs
index 85bf533df9..acd9eef972 100644
--- a/test/Sentry.Tests/HubTests.cs
+++ b/test/Sentry.Tests/HubTests.cs
@@ -1730,6 +1730,67 @@ public void CaptureFeedback_ConfigureScope_ScopeApplied(bool enabled)
         _fixture.Client.Received(enabled ? 1 : 0).CaptureFeedback(Arg.Any<SentryFeedback>(), Arg.Is<Scope>(s => s.Tags["foo"] == "bar"), Arg.Any<SentryHint>());
     }
 
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void CaptureAttachment_HubEnabled(bool enabled)
+    {
+        // Arrange
+        var hub = _fixture.GetSut();
+        if (!enabled)
+        {
+            hub.Dispose();
+        }
+
+        _fixture.Client.CaptureEnvelope(Arg.Any<Envelope>()).Returns(true);
+
+        var eventId = SentryId.Create();
+        var attachment = new SentryAttachment(
+            AttachmentType.Default,
+            new ByteAttachmentContent("test content"u8.ToArray()),
+            "test.txt",
+            "text/plain");
+
+        // Act
+        var result = hub.CaptureAttachment(eventId, attachment);
+
+        // Assert
+        result.Should().Be(enabled);
+        _fixture.Client.Received(enabled ? 1 : 0).CaptureEnvelope(Arg.Any<Envelope>());
+    }
+
+    [Fact]
+    public void CaptureAttachment_SentryIdEmpty_ReturnsFalse()
+    {
+        // Arrange
+        var hub = _fixture.GetSut();
+
+        var eventId = SentryId.Empty;
+        var attachment = new SentryAttachment(AttachmentType.Default, NullAttachmentContent.Instance, "test.txt", "text/plain");
+
+        // Act
+        var result = hub.CaptureAttachment(eventId, attachment);
+
+        // Assert
+        result.Should().Be(false);
+        _fixture.Client.DidNotReceive().CaptureEnvelope(Arg.Any<Envelope>());
+    }
+
+    [Fact]
+    public void CaptureAttachment_AttachmentNull_ReturnsFalse()
+    {
+        // Arrange
+        var hub = _fixture.GetSut();
+        var eventId = SentryId.Create();
+
+        // Act
+        var result = hub.CaptureAttachment(eventId, null!);
+
+        // Assert
+        result.Should().Be(false);
+        _fixture.Client.DidNotReceive().CaptureEnvelope(Arg.Any<Envelope>());
+    }
+
     [Theory]
     [InlineData(true)]
     [InlineData(false)]
diff --git a/test/Sentry.Tests/Protocol/Envelopes/EnvelopeTests.cs b/test/Sentry.Tests/Protocol/Envelopes/EnvelopeTests.cs
index d1715c54ff..60f2fb98a4 100644
--- a/test/Sentry.Tests/Protocol/Envelopes/EnvelopeTests.cs
+++ b/test/Sentry.Tests/Protocol/Envelopes/EnvelopeTests.cs
@@ -1090,4 +1090,26 @@ public async Task Serialization_RoundTrip_RecalculatesLengthHeader()
         Assert.Contains("""{"foo":"2020-01-01T00:00:00+01:00"}""", serialized1);
         Assert.Contains("""{"foo":"2020-01-01T00:00:00\u002B01:00"}""", serialized2);
     }
+
+    [Fact]
+    public void FromAttachment_ValidAttachment_CreatesEnvelope()
+    {
+        // Arrange
+        var eventId = SentryId.Create();
+        var attachment = new SentryAttachment(
+            AttachmentType.Default,
+            new ByteAttachmentContent("test content"u8.ToArray()),
+            "test.txt",
+            "text/plain");
+
+        // Act
+        using var envelope = Envelope.FromAttachment(eventId, attachment);
+
+        // Assert
+        envelope.TryGetEventId().Should().Be(eventId);
+        envelope.Items.Should().HaveCount(1);
+        envelope.Items[0].Header["type"].Should().Be("attachment");
+        envelope.Items[0].Header["filename"].Should().Be("test.txt");
+        envelope.Items[0].Header["content_type"].Should().Be("text/plain");
+    }
 }