diff --git a/packages/sveltekit/src/server-common/integrations/svelteKitSpans.ts b/packages/sveltekit/src/server-common/integrations/svelteKitSpans.ts
index c38108c75542..fe5d1ed31e23 100644
--- a/packages/sveltekit/src/server-common/integrations/svelteKitSpans.ts
+++ b/packages/sveltekit/src/server-common/integrations/svelteKitSpans.ts
@@ -1,5 +1,9 @@
-import type { Integration, SpanJSON, SpanOrigin } from '@sentry/core';
-import { SEMANTIC_ATTRIBUTE_SENTRY_OP, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '@sentry/core';
+import type { Integration, SpanJSON, SpanOrigin, StreamedSpanJSON } from '@sentry/core';
+import {
+  safeSetSpanJSONAttributes,
+  SEMANTIC_ATTRIBUTE_SENTRY_OP,
+  SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN,
+} from '@sentry/core';
 
 /**
  * A small integration that preprocesses spans so that SvelteKit-generated spans
@@ -20,6 +24,9 @@ export function svelteKitSpansIntegration(): Integration {
         event.spans?.forEach(_enhanceKitSpan);
       }
     },
+    processSpan(span) {
+      _enhanceKitSpanStreamed(span);
+    },
   };
 }
 
@@ -28,51 +35,63 @@ export function svelteKitSpansIntegration(): Integration {
  * @exported for testing
  */
 export function _enhanceKitSpan(span: SpanJSON): void {
-  let op: string | undefined = undefined;
-  let origin: SpanOrigin | undefined = undefined;
-
-  const spanName = span.description;
+  const { op, origin } = _getKitSpanEnhancement(span.description);
 
   const previousOp = span.op || span.data[SEMANTIC_ATTRIBUTE_SENTRY_OP];
   const previousOrigin = span.origin || span.data[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN];
 
+  if (!previousOp && op) {
+    span.op = op;
+    span.data[SEMANTIC_ATTRIBUTE_SENTRY_OP] = op;
+  }
+
+  if ((!previousOrigin || previousOrigin === 'manual') && origin) {
+    span.origin = origin;
+    span.data[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN] = origin;
+  }
+}
+
+/**
+ * Streaming-mode counterpart of {@link _enhanceKitSpan} operating on {@link StreamedSpanJSON}.
+ * @exported for testing
+ */
+export function _enhanceKitSpanStreamed(span: StreamedSpanJSON): void {
+  const { op, origin } = _getKitSpanEnhancement(span.name);
+  const previousOrigin = span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN] as SpanOrigin | undefined;
+
+  if (op) {
+    safeSetSpanJSONAttributes(span, { [SEMANTIC_ATTRIBUTE_SENTRY_OP]: op });
+  }
+
+  if (previousOrigin === 'manual' && origin) {
+    // `safeSetSpanJSONAttributes` skips existing keys, so overwrite the 'manual' sentinel directly.
+    span.attributes![SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN] = origin;
+  } else {
+    safeSetSpanJSONAttributes(span, { [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: origin });
+  }
+}
+
+function _getKitSpanEnhancement(spanName: string | undefined): {
+  op?: string;
+  origin?: SpanOrigin;
+} {
   switch (spanName) {
     case 'sveltekit.resolve':
-      op = 'function.sveltekit.resolve';
-      origin = 'auto.http.sveltekit';
-      break;
+      return { op: 'function.sveltekit.resolve', origin: 'auto.http.sveltekit' };
     case 'sveltekit.load':
-      op = 'function.sveltekit.load';
-      origin = 'auto.function.sveltekit.load';
-      break;
+      return { op: 'function.sveltekit.load', origin: 'auto.function.sveltekit.load' };
     case 'sveltekit.form_action':
-      op = 'function.sveltekit.form_action';
-      origin = 'auto.function.sveltekit.action';
-      break;
+      return { op: 'function.sveltekit.form_action', origin: 'auto.function.sveltekit.action' };
     case 'sveltekit.remote.call':
-      op = 'function.sveltekit.remote';
-      origin = 'auto.rpc.sveltekit.remote';
-      break;
+      return { op: 'function.sveltekit.remote', origin: 'auto.rpc.sveltekit.remote' };
     case 'sveltekit.handle.root':
       // We don't want to overwrite the root handle span at this point since
       // we already enhance the root span in our `sentryHandle` hook.
-      break;
-    default: {
+      return {};
+    default:
       if (spanName?.startsWith('sveltekit.handle.sequenced.')) {
-        op = 'function.sveltekit.handle';
-        origin = 'auto.function.sveltekit.handle';
+        return { op: 'function.sveltekit.handle', origin: 'auto.function.sveltekit.handle' };
       }
-      break;
-    }
-  }
-
-  if (!previousOp && op) {
-    span.op = op;
-    span.data[SEMANTIC_ATTRIBUTE_SENTRY_OP] = op;
-  }
-
-  if ((!previousOrigin || previousOrigin === 'manual') && origin) {
-    span.origin = origin;
-    span.data[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN] = origin;
+      return {};
   }
 }
diff --git a/packages/sveltekit/test/server-common/integrations/svelteKitSpans.test.ts b/packages/sveltekit/test/server-common/integrations/svelteKitSpans.test.ts
index 0d95cb3d6fb6..b051d613aad1 100644
--- a/packages/sveltekit/test/server-common/integrations/svelteKitSpans.test.ts
+++ b/packages/sveltekit/test/server-common/integrations/svelteKitSpans.test.ts
@@ -1,14 +1,19 @@
-import type { SpanJSON, TransactionEvent } from '@sentry/core';
+import type { SpanJSON, StreamedSpanJSON, TransactionEvent } from '@sentry/core';
 import { SEMANTIC_ATTRIBUTE_SENTRY_OP, SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '@sentry/core';
 import { describe, expect, it } from 'vitest';
-import { _enhanceKitSpan, svelteKitSpansIntegration } from '../../../src/server-common/integrations/svelteKitSpans';
+import {
+  _enhanceKitSpan,
+  _enhanceKitSpanStreamed,
+  svelteKitSpansIntegration,
+} from '../../../src/server-common/integrations/svelteKitSpans';
 
 describe('svelteKitSpansIntegration', () => {
-  it('has a name and a preprocessEventHook', () => {
+  it('has a name and a preprocessEvent and processSpan hook', () => {
     const integration = svelteKitSpansIntegration();
 
     expect(integration.name).toBe('SvelteKitSpansEnhancement');
     expect(typeof integration.preprocessEvent).toBe('function');
+    expect(typeof integration.processSpan).toBe('function');
   });
 
   it('enhances spans from SvelteKit', () => {
@@ -169,4 +174,106 @@ describe('svelteKitSpansIntegration', () => {
       expect(span.data[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('custom.op');
     });
   });
+
+  describe('_enhanceKitSpanStreamed', () => {
+    function makeStreamedSpan(overrides: Partial<StreamedSpanJSON> = {}): StreamedSpanJSON {
+      return {
+        name: 'unspecified',
+        span_id: '123',
+        trace_id: 'abc',
+        start_timestamp: 0,
+        end_timestamp: 1,
+        status: 'ok',
+        is_segment: false,
+        attributes: {},
+        ...overrides,
+      };
+    }
+
+    it.each([
+      ['sveltekit.resolve', 'function.sveltekit.resolve', 'auto.http.sveltekit'],
+      ['sveltekit.load', 'function.sveltekit.load', 'auto.function.sveltekit.load'],
+      ['sveltekit.form_action', 'function.sveltekit.form_action', 'auto.function.sveltekit.action'],
+      ['sveltekit.remote.call', 'function.sveltekit.remote', 'auto.rpc.sveltekit.remote'],
+      ['sveltekit.handle.sequenced.0', 'function.sveltekit.handle', 'auto.function.sveltekit.handle'],
+      ['sveltekit.handle.sequenced.myHandler', 'function.sveltekit.handle', 'auto.function.sveltekit.handle'],
+    ])('enhances %s span with the correct op and origin', (spanName, op, origin) => {
+      const span = makeStreamedSpan({ name: spanName, attributes: { someAttribute: 'someValue' } });
+
+      _enhanceKitSpanStreamed(span);
+
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe(op);
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe(origin);
+    });
+
+    it("doesn't change spans from other origins", () => {
+      const span = makeStreamedSpan({ name: 'someOtherSpan' });
+
+      _enhanceKitSpanStreamed(span);
+
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBeUndefined();
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBeUndefined();
+    });
+
+    it("doesn't overwrite the sveltekit.handle.root span", () => {
+      const rootHandleSpan = makeStreamedSpan({
+        name: 'sveltekit.handle.root',
+        attributes: {
+          [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'http.server',
+          [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.http.sveltekit',
+        },
+      });
+
+      _enhanceKitSpanStreamed(rootHandleSpan);
+
+      expect(rootHandleSpan.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('http.server');
+      expect(rootHandleSpan.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.http.sveltekit');
+    });
+
+    it("doesn't enhance unrelated spans", () => {
+      const span = makeStreamedSpan({
+        name: 'someOtherSpan',
+        attributes: {
+          [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'db',
+          [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.db.pg',
+        },
+      });
+
+      _enhanceKitSpanStreamed(span);
+
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('db');
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.db.pg');
+    });
+
+    it("doesn't overwrite already set ops or origins on sveltekit spans", () => {
+      // for example, if users manually set this (for whatever reason)
+      const span = makeStreamedSpan({
+        name: 'sveltekit.resolve',
+        attributes: {
+          [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'custom.op',
+          [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'auto.custom.origin',
+        },
+      });
+
+      _enhanceKitSpanStreamed(span);
+
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('custom.op');
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.custom.origin');
+    });
+
+    it('overwrites previously set "manual" origins on sveltekit spans', () => {
+      const span = makeStreamedSpan({
+        name: 'sveltekit.resolve',
+        attributes: {
+          [SEMANTIC_ATTRIBUTE_SENTRY_OP]: 'custom.op',
+          [SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]: 'manual',
+        },
+      });
+
+      _enhanceKitSpanStreamed(span);
+
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_OP]).toBe('custom.op');
+      expect(span.attributes?.[SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN]).toBe('auto.http.sveltekit');
+    });
+  });
 });