diff --git a/lib/opentelemetry/trace/recording_span.lua b/lib/opentelemetry/trace/recording_span.lua
index a1f402b..35fdd82 100644
--- a/lib/opentelemetry/trace/recording_span.lua
+++ b/lib/opentelemetry/trace/recording_span.lua
@@ -21,15 +21,16 @@ local mt = {
 -- @config              optional config
 --                          config.kind: span kind
 --                          config.attributes: span attributes
+-- @start_time          optional start time
 -- @return              span
 ------------------------------------------------------------------
-function _M.new(tracer, parent_ctx, ctx, name, config)
+function _M.new(tracer, parent_ctx, ctx, name, config, start_time)
     local self = {
         tracer = tracer,
         parent_ctx = parent_ctx,
         ctx = ctx,
         name = name,
-        start_time = util.time_nano(),
+        start_time = start_time or util.time_nano(),
         end_time = 0,
         kind = span_kind.validate(config.kind),
         attributes = config.attributes or {},
diff --git a/lib/opentelemetry/trace/tracer.lua b/lib/opentelemetry/trace/tracer.lua
index 0114aa3..c28636d 100644
--- a/lib/opentelemetry/trace/tracer.lua
+++ b/lib/opentelemetry/trace/tracer.lua
@@ -19,7 +19,7 @@ function _M.new(provider, il)
     return setmetatable(self, mt)
 end
 
-local function new_span(self, context, name, config)
+local function new_span(self, context, name, config, start_time)
     local span_context = context:span_context()
     if not config then
         config = {}
@@ -52,7 +52,7 @@ local function new_span(self, context, name, config)
     if not sampling_result:is_recording() then
         span = non_recording_span_new(self, new_span_context)
     else
-        span = recording_span_new(self, span_context, new_span_context, name, config)
+        span = recording_span_new(self, span_context, new_span_context, name, config, start_time)
     end
 
     return context:with_span(span), span
@@ -66,12 +66,13 @@ end
 -- @span_start_config   [optional]
 --                          span_start_config.kind: opentelemetry.trace.span_kind.*
 --                          span_start_config.attributes: a list of attribute
+-- @start_time          [optional] start time
 -- @return
 --                      context: new context with span
 --                      span
 ------------------------------------------------------------------
-function _M.start(self, context, span_name, span_start_config)
-    return new_span(self, context, span_name, span_start_config)
+function _M.start(self, context, span_name, span_start_config, start_time)
+    return new_span(self, context, span_name, span_start_config, start_time)
 end
 
 return _M
diff --git a/t/trace/span_finish_timestamp.t b/t/trace/span_timestamps.t
similarity index 79%
rename from t/trace/span_finish_timestamp.t
rename to t/trace/span_timestamps.t
index ef5961e..c8efefd 100644
--- a/t/trace/span_finish_timestamp.t
+++ b/t/trace/span_timestamps.t
@@ -8,7 +8,7 @@ run_tests();
 
 __DATA__
 
-=== TEST 1: span end timestamp can be set explicitly
+=== TEST 1: span start and end timestamps can be set explicitly
 --- config
 location = /t {
     content_by_lua_block {
@@ -19,8 +19,11 @@ location = /t {
         local attr = require("opentelemetry.attribute")
         local tracer = tracer_provider:tracer("unit_test")
         local context, recording_span = tracer:start(context, "recording",
-            {kind = span_kind.producer, attributes = {attr.string("key", "value")}})
+            {kind = span_kind.producer, attributes = {attr.string("key", "value")}}, 123456788)
         context.sp:finish(123456789)
+        if context.sp.start_time ~= 123456788 then
+            ngx.log(ngx.ERR, "start time should have been 123456788, was " .. context.sp.start_time)
+        end
         if context.sp.end_time ~= 123456789 then
             ngx.log(ngx.ERR, "end time should have been 123456789, was " .. context.sp.end_time)
         end