diff --git a/q2_types/per_sample_sequences/_transformer.py b/q2_types/per_sample_sequences/_transformer.py
index 6e657c67..066ad64f 100644
--- a/q2_types/per_sample_sequences/_transformer.py
+++ b/q2_types/per_sample_sequences/_transformer.py
@@ -94,6 +94,12 @@ def _11(dirfmt: CasavaOneEightLanelessPerSampleDirFmt) \
         dirfmt, SingleLanePerSamplePairedEndFastqDirFmt, parse_lane=False)
 
 
+@plugin.register_transformer
+def _12(dirfmt: SingleLanePerSampleSingleEndFastqDirFmt) \
+        -> CasavaOneEightSingleLanePerSampleDirFmt:
+    return CasavaOneEightSingleLanePerSampleDirFmt(str(dirfmt), mode='r')
+
+
 @plugin.register_transformer
 def _5(dirfmt: SingleLanePerSamplePairedEndFastqDirFmt) \
         -> SingleLanePerSampleSingleEndFastqDirFmt:
@@ -351,7 +357,7 @@ def _9(fmt: PairedEndFastqManifestPhred64) \
 
 
 @plugin.register_transformer
-def _12(dirfmt: SingleLanePerSampleSingleEndFastqDirFmt) \
+def _27(dirfmt: SingleLanePerSampleSingleEndFastqDirFmt) \
         -> QIIME1DemuxDirFmt:
     with dirfmt.manifest.view(FastqManifestFormat).open() as fh:
         input_manifest = _parse_and_validate_manifest(fh, single_end=True,
diff --git a/q2_types/per_sample_sequences/tests/test_transformer.py b/q2_types/per_sample_sequences/tests/test_transformer.py
index 3bc8fbec..e5faaa6c 100644
--- a/q2_types/per_sample_sequences/tests/test_transformer.py
+++ b/q2_types/per_sample_sequences/tests/test_transformer.py
@@ -138,11 +138,11 @@ def test_casava_one_eight_single_lane_per_sample_dirfmt_to_slpssefdf(self):
         for act, exp in zip(obs, input):
             self.assertEqual(act, exp)
 
-    def test_casava_one_eight_single_lane_per_sample_dirfmt_to_slpspefdf(self):
+    def test_slpssefdf_to_casava_one_eight_single_lane_per_sample_dirfmt(self):
         filenames = ('Human-Kneecap_S1_L001_R1_001.fastq.gz',)
         input, obs = self.transform_format(
-            CasavaOneEightSingleLanePerSampleDirFmt,
-            SingleLanePerSamplePairedEndFastqDirFmt, filenames=filenames
+            SingleLanePerSampleSingleEndFastqDirFmt,
+            CasavaOneEightSingleLanePerSampleDirFmt, filenames=filenames
         )
 
         input = skbio.io.read(