@@ -187,7 +187,6 @@ class DataCollectionUserOptions(TypedDict, total=False):
         frame_context_lines: int
 
     class DataCollection(TypedDict):
-        provided_by_user: bool
         user_info: bool
         cookies: "KeyValueCollectionBehaviour"
         http_headers: "HttpHeadersCollectionBehaviour"
 
@@ -19,7 +19,6 @@
     ClientConstructor,
 )
 from sentry_sdk.data_collection import (
-    _map_from_send_default_pii,
     _resolve_data_collection,
 )
 from sentry_sdk.envelope import Envelope, Item
@@ -153,9 +152,10 @@ class BaseClient:
     spotlight: "Optional[SpotlightClient]" = None
 
     def __init__(self, options: "Optional[Dict[str, Any]]" = None) -> None:
-        self.options: "Dict[str, Any]" = (
-            options if options is not None else DEFAULT_OPTIONS
-        )
+        if options is None:
+            options = dict(DEFAULT_OPTIONS)
+            options["data_collection"] = _resolve_data_collection(options)
+        self.options: "Dict[str, Any]" = options
 
         self.transport: "Optional[Transport]" = None
         self.monitor: "Optional[Monitor]" = None
@@ -178,9 +178,6 @@ def dsn(self) -> "Optional[str]":
     def parsed_dsn(self) -> "Optional[Dsn]":
         return None
 
-    def should_send_default_pii(self) -> bool:
-        return False
-
     def is_active(self) -> bool:
         """
         .. versionadded:: 2.0.0
@@ -366,18 +363,8 @@ def _record_lost_event(
             self.spotlight = setup_spotlight(self.options)
             if self.spotlight is not None and not self.options["dsn"]:
                 sample_all = lambda *_args, **_kwargs: 1.0
-                self.options["send_default_pii"] = True
                 self.options["error_sampler"] = sample_all
                 self.options["traces_sampler"] = sample_all
-                # data_collection was resolved in _get_options() before this
-                # spotlight override flipped send_default_pii on. Re-derive it so
-                # data_collection agrees with should_send_default_pii() in
-                # DSN-less spotlight mode (only when the user did not set
-                # data_collection explicitly).
-                if not self.options["data_collection"]["provided_by_user"]:
-                    self.options["data_collection"] = _map_from_send_default_pii(
-                        send_default_pii=True
-                    )
 
             self.session_flusher = SessionFlusher(capture_func=_capture_envelope)
 
@@ -451,14 +438,6 @@ def is_active(self) -> bool:
         """
         return True
 
-    def should_send_default_pii(self) -> bool:
-        """
-        .. versionadded:: 2.0.0
-
-        Returns whether the client should send default PII (Personally Identifiable Information) data to Sentry.
-        """
-        return self.options.get("send_default_pii") or False
-
     @property
     def dsn(self) -> "Optional[str]":
         """Returns the configured DSN as string."""
 
@@ -1361,7 +1361,7 @@ def __init__(
         transport_queue_size: int = DEFAULT_QUEUE_SIZE,
         sample_rate: float = 1.0,
         send_default_pii: "Optional[bool]" = None,
-        data_collection: "Optional[DataCollectionUserOptions]" = None,
+        data_collection: "Optional[DataCollectionUserOptions]" = {},
         http_proxy: "Optional[str]" = None,
         https_proxy: "Optional[str]" = None,
         ignore_errors: "Sequence[Union[type, str]]" = [],  # noqa: B006
@@ -1505,12 +1505,10 @@ def __init__(
             managing `Sensitive Data <https://docs.sentry.io/data-management/sensitive-data/>`_.
 
         :param data_collection: Structured configuration controlling what data integrations collect
-            automatically, superseding `send_default_pii`. Passing a dict opts into the feature; omitted
-            fields use their defaults (most categories are collected, with the sensitive denylist
-            scrubbing values). When it is not set, the SDK derives behaviour from `send_default_pii` so
-            that upgrading changes nothing. Restrict collection per category (user identity, cookies,
+            automatically. Omitted fields use their defaults (most categories are collected, with the sensitive denylist
+            scrubbing values). Restrict collection per category (user identity, cookies,
             HTTP headers/bodies, query params, generative AI inputs/outputs, stack frame variables,
-            source context). If `send_default_pii` is also set, `data_collection` takes precedence.
+            source context).
 
             Example::
 
 
@@ -5,21 +5,10 @@
 "Data Collection" spec
 (https://develop.sentry.dev/sdk/foundations/client/data-collection/).
 
-``data_collection`` supersedes the single ``send_default_pii`` boolean with a
-structured configuration that lets users enable or restrict automatically
+``data_collection`` lets users enable or restrict automatically
 collected data by category (user identity, cookies, HTTP headers, URL query params,
 HTTP bodies, generative AI inputs/outputs, stack frame variables, source
 context).
-
-Resolution precedence (see :func:`_resolve_data_collection`):
-
-* ``data_collection`` set, ``send_default_pii`` unset -> honour ``data_collection``
-  using the spec defaults for any omitted field.
-* ``send_default_pii`` set, ``data_collection`` unset -> derive a
-  resolved ``DataCollection`` that mirrors what ``send_default_pii`` collects today.
-* neither set -> treated as ``send_default_pii=False``.
-* both set -> ``data_collection`` wins (it is the single source of truth); a
-  ``DeprecationWarning`` is emitted for ``send_default_pii``.
 """
 
 from typing import TYPE_CHECKING, Any, Dict, List, Mapping, Optional, Union, cast
@@ -149,37 +138,7 @@ def _apply_key_value_collection_filtering(
     return result
 
 
-def _map_from_send_default_pii(*, send_default_pii: bool) -> "DataCollection":
-    """
-    Build a fully-resolved ``DataCollection`` dict that mirrors the data
-    ``send_default_pii`` collects today. Used when ``data_collection`` is not
-    provided explicitly.
-    """
-    terms = [] if send_default_pii else ["forwarded", "-ip", "remote-", "via", "-user"]
-
-    return {
-        "provided_by_user": False,
-        "user_info": send_default_pii,
-        "cookies": {"mode": "denylist", "terms": terms},
-        # Headers are collected in both PII modes today (sensitive ones filtered
-        # when PII is off), so this never maps to "off".
-        "http_headers": {
-            "request": {"mode": "denylist", "terms": terms},
-        },
-        # Bodies are collected regardless of PII today, bounded by
-        # ``max_request_body_size``.
-        "http_bodies": list(_ALL_HTTP_BODY_TYPES),
-        "url_query_params": {"mode": "denylist", "terms": terms},
-        "graphql": {"document": send_default_pii, "variables": send_default_pii},
-        "gen_ai": {"inputs": send_default_pii, "outputs": send_default_pii},
-        "database_query_data": send_default_pii,
-        "queues": send_default_pii,
-        "stack_frame_variables": True,
-        "frame_context_lines": _DEFAULT_FRAME_CONTEXT_LINES,
-    }
-
-
-def _resolve_explicit(
+def _resolve(
     d: "dict[str, Any]",
 ) -> "DataCollection":
     """
@@ -214,7 +173,6 @@ def _resolve_explicit(
     )
 
     return {
-        "provided_by_user": True,
         "user_info": d.get("user_info", True),
         "cookies": _kvcb_from_value(d.get("cookies") or {}),
         "http_headers": _http_headers_from_value(d.get("http_headers") or {}),
@@ -280,37 +238,20 @@ def _resolve_data_collection(options: "Dict[str, Any]") -> "DataCollection":
     """
     Resolve the effective ``DataCollection`` dict from client ``options``.
 
-    Reads ``data_collection``, ``send_default_pii`` and returns a fully-resolved
-    dict with concrete values for every field.
+    Reads ``data_collection`` and returns a fully-resolved dict with concrete values for every field.
 
     ``data_collection`` must be a plain ``dict``.
 
     Must be called exactly once per options dict, before ``client._get_options``
-    overwrites ``options["data_collection"]`` with the resolved result. Feeding an
-    already-resolved dict back in would flip ``provided_by_user`` to ``True``.
+    overwrites ``options["data_collection"]`` with the resolved result.
     """
-    from sentry_sdk.utils import deprecation_warning
-
     user_dc = options.get("data_collection")
-    if user_dc is None:
-        user_dc = options.get("_experiments", {}).get("data_collection")
 
-    send_default_pii = options.get("send_default_pii")
-
-    if user_dc is not None:
-        if not isinstance(user_dc, dict):
-            raise TypeError(
-                "`data_collection` must be a dict, got {!r}.".format(
-                    type(user_dc).__name__
-                )
-            )
-        if send_default_pii is not None:
-            deprecation_warning(
-                "`send_default_pii` is deprecated and ignored when "
-                "`data_collection` is set.",
-            )
-        return _resolve_explicit(
-            user_dc,
+    if not isinstance(user_dc, dict):
+        raise TypeError(
+            "`data_collection` must be a dict, got {!r}.".format(type(user_dc).__name__)
         )
 
-    return _map_from_send_default_pii(send_default_pii=bool(send_default_pii))
+    return _resolve(
+        user_dc,
+    )
@@ -12,7 +12,6 @@
     get_current_span,
 )
 from sentry_sdk.utils import (
-    has_data_collection_enabled,
     parse_version,
 )
 
@@ -116,12 +115,10 @@ def event_processor(event: "Event", hint: "Dict[str, Any]") -> "Event":
                 if "cookies" in info:
                     request_info["cookies"] = info["cookies"]
                 if "data" in info:
-                    attach_request_data = True
-                    if has_data_collection_enabled(client.options):
-                        attach_request_data = (
-                            "incoming_request"
-                            in client.options["data_collection"]["http_bodies"]
-                        )
+                    attach_request_data = (
+                        "incoming_request"
+                        in client.options["data_collection"]["http_bodies"]
+                    )
 
                     if attach_request_data:
                         request_info["data"] = info["data"]
@@ -142,12 +139,9 @@ def event_processor(event: "Event", hint: "Dict[str, Any]") -> "Event":
         current_span = get_current_span()
 
         if type(current_span) is Span:
-            attach_request_data = True
-            if has_data_collection_enabled(client.options):
-                attach_request_data = (
-                    "incoming_request"
-                    in client.options["data_collection"]["http_bodies"]
-                )
+            attach_request_data = (
+                "incoming_request" in client.options["data_collection"]["http_bodies"]
+            )
 
             if attach_request_data:
                 request_body = _get_cached_request_body_attribute(
 
@@ -166,7 +166,6 @@ def on_operation(self) -> "Generator[None, None, None]":
             return
 
         additional_attributes: "dict[str, Any]" = {}
-
         if client.options["data_collection"]["graphql"]["document"]:
             additional_attributes["graphql.document"] = self.execution_context.query
 
@@ -395,7 +394,11 @@ def _make_response_event_processor(
     def inner(event: "Event", hint: "dict[str, Any]") -> "Event":
         client_options = sentry_sdk.get_client().options
         with capture_internal_exceptions():
-            if "outgoing_response" in client_options["data_collection"]["http_bodies"]:
+            collect_response = (
+                "outgoing_response" in client_options["data_collection"]["http_bodies"]
+            )
+
+            if collect_response:
                 contexts = event.setdefault("contexts", {})
                 contexts["response"] = {"data": response_data}
 
 
@@ -43,7 +43,6 @@
     event_from_exception,
     exc_info_from_error,
     format_attribute,
-    has_data_collection_enabled,
     logger,
 )
 
@@ -1443,10 +1442,7 @@ def _apply_user_attributes_to_telemetry(
             attributes = telemetry._attributes
 
         client_options = sentry_sdk.get_client().options
-        if has_data_collection_enabled(client_options):
-            if not client_options["data_collection"]["user_info"] or self._user is None:
-                return
-        elif not should_send_default_pii() or self._user is None:
+        if not client_options["data_collection"]["user_info"] or self._user is None:
             return
 
         for attribute_name, user_attribute in (
@@ -1874,11 +1870,6 @@ def use_isolation_scope(isolation_scope: "Scope") -> "Generator[Scope, None, Non
             capture_internal_exception(sys.exc_info())
 
 
-def should_send_default_pii() -> bool:
-    """Shortcut for `Scope.get_client().should_send_default_pii()`."""
-    return Scope.get_client().should_send_default_pii()
-
-
 # Circular imports
 from sentry_sdk.client import NonRecordingClient
 
 
@@ -23,7 +23,6 @@
     _module_in_list,
     capture_internal_exceptions,
     filename_for_module,
-    has_data_collection_enabled,
     is_sentry_url,
     is_valid_sample_rate,
     logger,
@@ -185,26 +184,18 @@ def get_url_attributes_legacy(
 ) -> "Attributes":
     """Build the `url.*` span attributes for an outgoing HTTP request.
 
-    The query string is only included when the user has opted into collecting
-    it, either through `data_collection` (in which case the configured
-    filtering is applied) or through the legacy `send_default_pii`.
+    The query string is filtered according to `data_collection`.
     """
     attributes: "Attributes" = {}
     if parsed_url is None:
         return attributes
 
-    query: "Optional[str]"
-    if has_data_collection_enabled(client.options):
-        query = None
-        if parsed_url.query:
-            query = _apply_data_collection_filtering_to_query_string(
-                query_string=parsed_url.query,
-                behaviour=client.options["data_collection"]["url_query_params"],
-            )
-    elif client.should_send_default_pii():
-        query = parsed_url.query
-    else:
-        return attributes
+    query: "Optional[str]" = None
+    if parsed_url.query:
+        query = _apply_data_collection_filtering_to_query_string(
+            query_string=parsed_url.query,
+            behaviour=client.options["data_collection"]["url_query_params"],
+        )
 
     url_full = parsed_url.url
     if query:
 
@@ -65,7 +65,6 @@
 
     from sentry_sdk._types import (
         AttributeValue,
-        DataCollection,
         Event,
         ExcInfo,
         Hint,
@@ -477,11 +476,7 @@ def get_lines_from_file(
 ) -> "Tuple[List[Annotated[str]], Optional[Annotated[str]], List[Annotated[str]]]":
     client_options = sentry_sdk.get_client().options
 
-    # This is the default pre-data collection. Should be removed once data collection
-    # is fully released
-    context_lines = 5
-    if has_data_collection_enabled(client_options):
-        context_lines = client_options["data_collection"]["frame_context_lines"]
+    context_lines = client_options["data_collection"]["frame_context_lines"]
 
     source = None
     if loader is not None and hasattr(loader, "get_source"):
@@ -1910,19 +1905,6 @@ def serialize_item(
         return str(data)
 
 
-def has_data_collection_enabled(options: "Optional[dict[str, Any]]") -> bool:
-    if options is None:
-        return False
-
-    data_collection: "Optional[DataCollection]" = options.get("data_collection")
-    # Client options are resolved as part of client initialization, so `data_collection`
-    # being None could be that the user just didn't provide it.
-    # `provided_by_user` is what actually records whether the user actually configured it.
-    return data_collection is not None and data_collection.get(
-        "provided_by_user", False
-    )
-
-
 def get_before_send_log(
     options: "Optional[dict[str, Any]]",
 ) -> "Optional[Callable[[Log, Hint], Optional[Log]]]":