diff --git a/src/core/errors.py b/src/core/errors.py
index 3f53364..a619191 100644
--- a/src/core/errors.py
+++ b/src/core/errors.py
@@ -385,3 +385,26 @@ class InternalError(ProblemDetailError):
     uri = "https://openml.org/problems/internal-error"
     title = "Internal Server Error"
     _default_status_code = HTTPStatus.INTERNAL_SERVER_ERROR
+
+
+# =============================================================================
+# Run Errors
+# =============================================================================
+
+
+class RunNotFoundError(ProblemDetailError):
+    """Raised when a run cannot be found."""
+
+    uri = "https://openml.org/problems/run-not-found"
+    title = "Run Not Found"
+    _default_status_code = HTTPStatus.PRECONDITION_FAILED
+    _default_code = 571
+
+
+class RunTraceNotFoundError(ProblemDetailError):
+    """Raised when trace data for a run cannot be found."""
+
+    uri = "https://openml.org/problems/run-trace-not-found"
+    title = "Run Trace Not Found"
+    _default_status_code = HTTPStatus.PRECONDITION_FAILED
+    _default_code = 572
diff --git a/src/database/runs.py b/src/database/runs.py
new file mode 100644
index 0000000..d0fb1f2
--- /dev/null
+++ b/src/database/runs.py
@@ -0,0 +1,40 @@
+"""Database queries for run-related data."""
+
+from collections.abc import Sequence
+from typing import cast
+
+from sqlalchemy import Row, text
+from sqlalchemy.ext.asyncio import AsyncConnection
+
+
+async def get(id_: int, expdb: AsyncConnection) -> Row | None:
+    """Check if a run exists by ID."""
+    row = await expdb.execute(
+        text(
+            """
+            SELECT 1
+            FROM `run`
+            WHERE `rid` = :run_id
+            """,
+        ),
+        parameters={"run_id": id_},
+    )
+    return row.one_or_none()
+
+
+async def get_trace(run_id: int, expdb: AsyncConnection) -> Sequence[Row]:
+    """Get trace rows for a run from the trace table."""
+    rows = await expdb.execute(
+        text(
+            """
+            SELECT `repeat`, `fold`, `iteration`, `setup_string`, `evaluation`, `selected`
+            FROM `trace`
+            WHERE `run_id` = :run_id
+            """,
+        ),
+        parameters={"run_id": run_id},
+    )
+    return cast(
+        "Sequence[Row]",
+        rows.all(),
+    )
diff --git a/src/main.py b/src/main.py
index 76a52ad..19a6c84 100644
--- a/src/main.py
+++ b/src/main.py
@@ -15,6 +15,7 @@
 from routers.openml.evaluations import router as evaluationmeasures_router
 from routers.openml.flows import router as flows_router
 from routers.openml.qualities import router as qualities_router
+from routers.openml.runs import router as runs_router
 from routers.openml.setups import router as setup_router
 from routers.openml.study import router as study_router
 from routers.openml.tasks import router as task_router
@@ -70,6 +71,7 @@ def create_api() -> FastAPI:
     app.include_router(flows_router)
     app.include_router(study_router)
     app.include_router(setup_router)
+    app.include_router(runs_router)
     return app
 
 
diff --git a/src/routers/openml/runs.py b/src/routers/openml/runs.py
new file mode 100644
index 0000000..03f51e4
--- /dev/null
+++ b/src/routers/openml/runs.py
@@ -0,0 +1,44 @@
+"""Endpoints for run-related data."""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends
+from sqlalchemy.ext.asyncio import AsyncConnection
+
+import database.runs
+from core.errors import RunNotFoundError, RunTraceNotFoundError
+from routers.dependencies import expdb_connection
+from schemas.runs import RunTrace, TraceIteration
+
+router = APIRouter(prefix="/runs", tags=["runs"])
+
+
+@router.get("/trace/{run_id}")
+async def get_run_trace(
+    run_id: int,
+    expdb: Annotated[AsyncConnection, Depends(expdb_connection)],
+) -> RunTrace:
+    """Get trace data for a run by run ID."""
+    if not await database.runs.get(run_id, expdb):
+        msg = f"Run {run_id} not found."
+        raise RunNotFoundError(msg)
+
+    trace_rows = await database.runs.get_trace(run_id, expdb)
+    if not trace_rows:
+        msg = f"No trace found for run {run_id}."
+        raise RunTraceNotFoundError(msg)
+
+    return RunTrace(
+        run_id=run_id,
+        trace=[
+            TraceIteration(
+                repeat=row.repeat,
+                fold=row.fold,
+                iteration=row.iteration,
+                setup_string=row.setup_string,
+                evaluation=row.evaluation,
+                selected=row.selected,
+            )
+            for row in trace_rows
+        ],
+    )
diff --git a/src/schemas/runs.py b/src/schemas/runs.py
new file mode 100644
index 0000000..857f492
--- /dev/null
+++ b/src/schemas/runs.py
@@ -0,0 +1,21 @@
+"""Pydantic schemas for run-related endpoints."""
+
+from pydantic import BaseModel
+
+
+class TraceIteration(BaseModel):
+    """A single trace iteration for a run."""
+
+    repeat: int
+    fold: int
+    iteration: int
+    setup_string: str | None
+    evaluation: float | None
+    selected: str
+
+
+class RunTrace(BaseModel):
+    """Trace data for a run."""
+
+    run_id: int
+    trace: list[TraceIteration]
diff --git a/tests/routers/openml/runs_test.py b/tests/routers/openml/runs_test.py
new file mode 100644
index 0000000..f82e6a0
--- /dev/null
+++ b/tests/routers/openml/runs_test.py
@@ -0,0 +1,49 @@
+"""Tests for the GET /runs/trace/{run_id} endpoint."""
+
+from http import HTTPStatus
+
+import httpx
+import pytest
+
+from core.errors import RunNotFoundError, RunTraceNotFoundError
+
+
+@pytest.mark.parametrize("run_id", [34])
+async def test_get_run_trace_success(run_id: int, py_api: httpx.AsyncClient) -> None:
+    """Test that trace data is returned for a run that has trace entries."""
+    response = await py_api.get(f"/runs/trace/{run_id}")
+    assert response.status_code == HTTPStatus.OK
+    body = response.json()
+    assert body["run_id"] == run_id
+    assert isinstance(body["trace"], list)
+    assert len(body["trace"]) > 0
+    first = body["trace"][0]
+    assert isinstance(first["repeat"], int)
+    assert isinstance(first["fold"], int)
+    assert isinstance(first["iteration"], int)
+    assert first["selected"] in ("true", "false")
+    assert first["evaluation"] is None or isinstance(first["evaluation"], float)
+
+
+@pytest.mark.parametrize("run_id", [24])
+async def test_get_run_trace_no_trace(run_id: int, py_api: httpx.AsyncClient) -> None:
+    """Test that 412 is returned for a run that exists but has no trace."""
+    response = await py_api.get(f"/runs/trace/{run_id}")
+    assert response.status_code == HTTPStatus.PRECONDITION_FAILED
+    body = response.json()
+    assert body["code"] == "572"  # RunTraceNotFoundError code
+    assert body["type"] == RunTraceNotFoundError.uri
+    assert body["title"] == RunTraceNotFoundError.title
+    assert body["status"] == HTTPStatus.PRECONDITION_FAILED
+
+
+@pytest.mark.parametrize("run_id", [999999])
+async def test_get_run_trace_run_not_found(run_id: int, py_api: httpx.AsyncClient) -> None:
+    """Test that 412 is returned when the run does not exist."""
+    response = await py_api.get(f"/runs/trace/{run_id}")
+    assert response.status_code == HTTPStatus.PRECONDITION_FAILED
+    body = response.json()
+    assert body["code"] == "571"  # RunNotFoundError code
+    assert body["type"] == RunNotFoundError.uri
+    assert body["title"] == RunNotFoundError.title
+    assert body["status"] == HTTPStatus.PRECONDITION_FAILED