diff --git a/lib/api.dart b/lib/api.dart
index 220f481e..7c59b27a 100644
--- a/lib/api.dart
+++ b/lib/api.dart
@@ -10,8 +10,6 @@ export 'src/api/resource/resource.dart' show Resource;
 export 'src/api/span_processors/span_processor.dart' show SpanProcessor;
 export 'src/api/trace/id_generator.dart' show IdGenerator;
 export 'src/api/trace/nonrecording_span.dart' show NonRecordingSpan;
-export 'src/api/trace/sampler.dart' show Sampler;
-export 'src/api/trace/sampling_result.dart' show Decision, SamplingResult;
 export 'src/api/trace/span.dart' show Span, SpanKind;
 export 'src/api/trace/span_context.dart' show SpanContext;
 export 'src/api/trace/span_id.dart' show SpanId;
diff --git a/lib/sdk.dart b/lib/sdk.dart
index 08086340..205c73df 100644
--- a/lib/sdk.dart
+++ b/lib/sdk.dart
@@ -12,11 +12,13 @@ export 'src/sdk/trace/exporters/console_exporter.dart' show ConsoleExporter;
 export 'src/sdk/trace/id_generator.dart' show IdGenerator;
 export 'src/sdk/trace/propagation/w3c_trace_context_propagator.dart'
     show W3CTraceContextPropagator;
-export 'src/sdk/trace/samplers/always_off_sampler.dart' show AlwaysOffSampler;
-export 'src/sdk/trace/samplers/always_on_sampler.dart' show AlwaysOnSampler;
-export 'src/sdk/trace/samplers/parent_based_sampler.dart'
+export 'src/sdk/trace/sampling/always_off_sampler.dart' show AlwaysOffSampler;
+export 'src/sdk/trace/sampling/always_on_sampler.dart' show AlwaysOnSampler;
+export 'src/sdk/trace/sampling/parent_based_sampler.dart'
     show ParentBasedSampler;
-export 'src/sdk/trace/samplers/sampling_result.dart' show SamplingResult;
+export 'src/sdk/trace/sampling/sampler.dart' show Sampler;
+export 'src/sdk/trace/sampling/sampling_result.dart'
+    show Decision, SamplingResult;
 export 'src/sdk/trace/span.dart' show Span;
 export 'src/sdk/trace/span_context.dart' show SpanContext;
 export 'src/sdk/trace/span_processors/batch_processor.dart'
diff --git a/lib/src/sdk/trace/samplers/sampling_result.dart b/lib/src/sdk/trace/samplers/sampling_result.dart
deleted file mode 100644
index 8657b568..00000000
--- a/lib/src/sdk/trace/samplers/sampling_result.dart
+++ /dev/null
@@ -1,13 +0,0 @@
-import '../../../../api.dart';
-import '../../../api/trace/sampling_result.dart' as api;
-
-class SamplingResult implements api.SamplingResult {
-  @override
-  final api.Decision decision;
-  @override
-  final List<Attribute> spanAttributes;
-  @override
-  final TraceState traceState;
-
-  SamplingResult(this.decision, this.spanAttributes, this.traceState);
-}
diff --git a/lib/src/sdk/trace/samplers/always_off_sampler.dart b/lib/src/sdk/trace/sampling/always_off_sampler.dart
similarity index 74%
rename from lib/src/sdk/trace/samplers/always_off_sampler.dart
rename to lib/src/sdk/trace/sampling/always_off_sampler.dart
index 7d875698..6d23ddd4 100644
--- a/lib/src/sdk/trace/samplers/always_off_sampler.dart
+++ b/lib/src/sdk/trace/sampling/always_off_sampler.dart
@@ -1,12 +1,12 @@
 import '../../../../api.dart' as api;
 import '../../../../sdk.dart' as sdk;
 
-class AlwaysOffSampler implements api.Sampler {
+class AlwaysOffSampler implements sdk.Sampler {
   @override
   String get description => 'AlwaysOffSampler';
 
   @override
-  api.SamplingResult shouldSample(
+  sdk.SamplingResult shouldSample(
       api.Context context,
       api.TraceId traceId,
       String spanName,
@@ -14,7 +14,7 @@ class AlwaysOffSampler implements api.Sampler {
       bool spanIsRemote,
       List<api.Attribute> spanAttributes,
       List<api.SpanLink> links) {
-    return sdk.SamplingResult(api.Decision.drop, spanAttributes,
+    return sdk.SamplingResult(sdk.Decision.drop, spanAttributes,
         context.spanContext?.traceState ?? sdk.TraceState.empty());
   }
 }
diff --git a/lib/src/sdk/trace/samplers/always_on_sampler.dart b/lib/src/sdk/trace/sampling/always_on_sampler.dart
similarity index 75%
rename from lib/src/sdk/trace/samplers/always_on_sampler.dart
rename to lib/src/sdk/trace/sampling/always_on_sampler.dart
index 5b4af13e..889714bb 100644
--- a/lib/src/sdk/trace/samplers/always_on_sampler.dart
+++ b/lib/src/sdk/trace/sampling/always_on_sampler.dart
@@ -1,12 +1,12 @@
 import '../../../../api.dart' as api;
 import '../../../../sdk.dart' as sdk;
 
-class AlwaysOnSampler implements api.Sampler {
+class AlwaysOnSampler implements sdk.Sampler {
   @override
   String get description => 'AlwaysOnSampler';
 
   @override
-  api.SamplingResult shouldSample(
+  sdk.SamplingResult shouldSample(
       api.Context context,
       api.TraceId traceId,
       String spanName,
@@ -14,7 +14,7 @@ class AlwaysOnSampler implements api.Sampler {
       bool spanIsRemote,
       List<api.Attribute> spanAttributes,
       List<api.SpanLink> spanLinks) {
-    return sdk.SamplingResult(api.Decision.recordAndSample, spanAttributes,
+    return sdk.SamplingResult(sdk.Decision.recordAndSample, spanAttributes,
         context.spanContext?.traceState ?? sdk.TraceState.empty());
   }
 }
diff --git a/lib/src/sdk/trace/samplers/parent_based_sampler.dart b/lib/src/sdk/trace/sampling/parent_based_sampler.dart
similarity index 87%
rename from lib/src/sdk/trace/samplers/parent_based_sampler.dart
rename to lib/src/sdk/trace/sampling/parent_based_sampler.dart
index 53d7896f..2519fba1 100644
--- a/lib/src/sdk/trace/samplers/parent_based_sampler.dart
+++ b/lib/src/sdk/trace/sampling/parent_based_sampler.dart
@@ -1,12 +1,12 @@
 import '../../../../api.dart' as api;
 import '../../../../sdk.dart' as sdk;
 
-class ParentBasedSampler implements api.Sampler {
-  final api.Sampler _root;
-  final api.Sampler _remoteParentSampled;
-  final api.Sampler _remoteParentNotSampled;
-  final api.Sampler _localParentSampled;
-  final api.Sampler _localParentNotSampled;
+class ParentBasedSampler implements sdk.Sampler {
+  final sdk.Sampler _root;
+  final sdk.Sampler _remoteParentSampled;
+  final sdk.Sampler _remoteParentNotSampled;
+  final sdk.Sampler _localParentSampled;
+  final sdk.Sampler _localParentNotSampled;
 
   ParentBasedSampler(this._root,
       {remoteParentSampled,
@@ -24,7 +24,7 @@ class ParentBasedSampler implements api.Sampler {
   String get description => 'ParentBasedSampler{root=${_root.description}}';
 
   @override
-  api.SamplingResult shouldSample(
+  sdk.SamplingResult shouldSample(
       api.Context context,
       api.TraceId traceId,
       String spanName,
diff --git a/lib/src/api/trace/sampler.dart b/lib/src/sdk/trace/sampling/sampler.dart
similarity index 79%
rename from lib/src/api/trace/sampler.dart
rename to lib/src/sdk/trace/sampling/sampler.dart
index 7596f306..02a10c9c 100644
--- a/lib/src/api/trace/sampler.dart
+++ b/lib/src/sdk/trace/sampling/sampler.dart
@@ -1,9 +1,10 @@
-import '../../../api.dart' as api;
+import '../../../../api.dart' as api;
+import '../../../../sdk.dart' as sdk;
 
 /// Represents an entity which determines whether a [api.Span] should be sampled
 /// and sent for collection.
 abstract class Sampler {
-  api.SamplingResult shouldSample(
+  sdk.SamplingResult shouldSample(
       api.Context context,
       api.TraceId traceId,
       String spanName,
diff --git a/lib/src/api/trace/sampling_result.dart b/lib/src/sdk/trace/sampling/sampling_result.dart
similarity index 51%
rename from lib/src/api/trace/sampling_result.dart
rename to lib/src/sdk/trace/sampling/sampling_result.dart
index e45cae06..28d868ce 100644
--- a/lib/src/api/trace/sampling_result.dart
+++ b/lib/src/sdk/trace/sampling/sampling_result.dart
@@ -1,4 +1,4 @@
-import '../../../api.dart' as api;
+import '../../../../api.dart' as api;
 
 enum Decision {
   drop,
@@ -6,10 +6,8 @@ enum Decision {
   recordAndSample,
 }
 
-/// Represents the result of a Sampler as to whether a Span should
-/// be processed for collection.
-abstract class SamplingResult {
-  final api.Decision decision;
+class SamplingResult {
+  final Decision decision;
   final List<api.Attribute> spanAttributes;
   final api.TraceState traceState;
 
diff --git a/lib/src/sdk/trace/tracer.dart b/lib/src/sdk/trace/tracer.dart
index 2cd783a6..38d96ff6 100644
--- a/lib/src/sdk/trace/tracer.dart
+++ b/lib/src/sdk/trace/tracer.dart
@@ -7,7 +7,7 @@ import '../../../sdk.dart' as sdk;
 class Tracer implements api.Tracer {
   final List<api.SpanProcessor> _processors;
   final api.Resource _resource;
-  final api.Sampler _sampler;
+  final sdk.Sampler _sampler;
   final api.IdGenerator _idGenerator;
   final api.InstrumentationLibrary _instrumentationLibrary;
   sdk.SpanLimits _spanLimits;
@@ -49,7 +49,7 @@ class Tracer implements api.Tracer {
 
     final samplerResult = _sampler.shouldSample(
         context, traceId, name, kind, false, attributes, links);
-    final traceFlags = (samplerResult.decision == api.Decision.recordAndSample)
+    final traceFlags = (samplerResult.decision == sdk.Decision.recordAndSample)
         ? api.TraceFlags.sampled
         : api.TraceFlags.none;
     final spanContext =
diff --git a/lib/src/sdk/trace/tracer_provider.dart b/lib/src/sdk/trace/tracer_provider.dart
index e1ee9102..d2140d92 100644
--- a/lib/src/sdk/trace/tracer_provider.dart
+++ b/lib/src/sdk/trace/tracer_provider.dart
@@ -6,14 +6,14 @@ class TracerProvider implements api.TracerProvider {
   final Map<String, api.Tracer> _tracers = {};
   List<api.SpanProcessor> _processors;
   api.Resource _resource;
-  api.Sampler _sampler;
+  sdk.Sampler _sampler;
   api.IdGenerator _idGenerator;
   sdk.SpanLimits _spanLimits;
 
   TracerProvider(
       {List<api.SpanProcessor> processors,
       api.Resource resource,
-      api.Sampler sampler,
+      sdk.Sampler sampler,
       api.IdGenerator idGenerator,
       sdk.SpanLimits spanLimits}) {
     _processors = processors ?? []; // Default to a no-op TracerProvider.
diff --git a/test/unit/sdk/samplers/always_off_sampler_test.dart b/test/unit/sdk/sampling/always_off_sampler_test.dart
similarity index 94%
rename from test/unit/sdk/samplers/always_off_sampler_test.dart
rename to test/unit/sdk/sampling/always_off_sampler_test.dart
index eb49cc58..8c233eb2 100644
--- a/test/unit/sdk/samplers/always_off_sampler_test.dart
+++ b/test/unit/sdk/sampling/always_off_sampler_test.dart
@@ -20,7 +20,7 @@ void main() {
     final result = sdk.AlwaysOffSampler().shouldSample(testContext, traceId,
         testSpan.name, api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.drop));
+    expect(result.decision, equals(sdk.Decision.drop));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState, same(traceState));
   });
@@ -49,7 +49,7 @@ void main() {
         false,
         attributesList, []);
 
-    expect(result.decision, equals(api.Decision.drop));
+    expect(result.decision, equals(sdk.Decision.drop));
     expect(result.spanAttributes, attributesList);
     expect(result.traceState.isEmpty, isTrue);
   });
diff --git a/test/unit/sdk/samplers/always_on_sampler_test.dart b/test/unit/sdk/sampling/always_on_sampler_test.dart
similarity index 92%
rename from test/unit/sdk/samplers/always_on_sampler_test.dart
rename to test/unit/sdk/sampling/always_on_sampler_test.dart
index c4fec32f..77a54835 100644
--- a/test/unit/sdk/samplers/always_on_sampler_test.dart
+++ b/test/unit/sdk/sampling/always_on_sampler_test.dart
@@ -20,7 +20,7 @@ void main() {
     final result = sdk.AlwaysOnSampler().shouldSample(testContext, traceId,
         testSpan.name, api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState, same(traceState));
   });
@@ -39,7 +39,7 @@ void main() {
     final result = sdk.AlwaysOnSampler().shouldSample(api.Context.root, traceId,
         testSpan.name, api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState.isEmpty, isTrue);
   });
diff --git a/test/unit/sdk/samplers/parent_based_sampler_test.dart b/test/unit/sdk/sampling/parent_based_sampler_test.dart
similarity index 92%
rename from test/unit/sdk/samplers/parent_based_sampler_test.dart
rename to test/unit/sdk/sampling/parent_based_sampler_test.dart
index 4eec10d7..2b4c42c3 100644
--- a/test/unit/sdk/samplers/parent_based_sampler_test.dart
+++ b/test/unit/sdk/sampling/parent_based_sampler_test.dart
@@ -27,7 +27,7 @@ void main() {
     final result = testSampler.shouldSample(testContext, traceId, testSpan.name,
         api.SpanKind.internal, false, null, []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals(null));
     expect(result.traceState.isEmpty, isTrue);
   });
@@ -45,7 +45,7 @@ void main() {
     final result = testSampler.shouldSample(api.Context.root, traceId,
         testSpan.name, api.SpanKind.internal, false, null, []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals(null));
     expect(result.traceState.isEmpty, isTrue);
   });
@@ -67,7 +67,7 @@ void main() {
     final result = testSampler.shouldSample(testContext, traceId, testSpan.name,
         api.SpanKind.internal, false, null, []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals(null));
     expect(result.traceState, same(traceState));
   });
@@ -89,7 +89,7 @@ void main() {
     final result = testSampler.shouldSample(testContext, traceId, testSpan.name,
         api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.drop));
+    expect(result.decision, equals(sdk.Decision.drop));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState, same(traceState));
   });
@@ -111,7 +111,7 @@ void main() {
     final result = testSampler.shouldSample(testContext, traceId, testSpan.name,
         api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.recordAndSample));
+    expect(result.decision, equals(sdk.Decision.recordAndSample));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState, same(traceState));
   });
@@ -133,7 +133,7 @@ void main() {
     final result = testSampler.shouldSample(testContext, traceId, testSpan.name,
         api.SpanKind.internal, false, [], []);
 
-    expect(result.decision, equals(api.Decision.drop));
+    expect(result.decision, equals(sdk.Decision.drop));
     expect(result.spanAttributes, equals([]));
     expect(result.traceState, same(traceState));
   });